Halep reached the 2014 French Open final, her first Grand Slam final, where she lost to Maria Sharapova in three sets. She also reached the final of the WTA Finals the same year, losing to Serena Williams in straight sets after having defeated her earlier in the tournament. Halep continued her success throughout the 2015 and 2016 seasons winning 3 titles in each respective season (including 2 Premier Mandatory titles) and remaining within the Top 10.
Simona Halep was born in Constanța Romania, to Stere and Tania Halep, a family of Aromanian descent. Her father, a former football player at Săgeata Stejaru playing in the lower leagues, owns a dairy products factory.
Halep started playing tennis at the age of four, in emulation of her older brother. At age 6, she was practicing daily. At age 16, she relocated to Bucharest to further her tennis career. She named Justine Henin and Andrei Pavel as two of her idols when she was younger.
She started the year 2008 playing in junior competitions, reaching the final in Nottinghill, where she lost to Arantxa Rus, then defeated Anastasia Pavlyuchenkova in the quarterfinals at the Australian Open Junior Championships, before losing in the semifinal to Jessica Moore. She went on to win a pair events in May and June. First, a victory in the finals at Trofeo Bonfiglio, winning over Bojana Jovanovski in two sets. Then, at the Roland Garros Junior Championships, she entered the main draw as the 9th seed. In the first round, she defeated Charlotte Rodier, then Karen Barbat from Denmark, and in the 3rd round Halep won against 5th seed Jessica Moore, in straight sets. In the quarterfinals, she beat 13th seed Ksenia Lykina, and in the semifinals, Halep defeated second seed Arantxa Rus. She closed things by winning the all–Romanian final in three sets against 10th seed Elena Bogdan.
She also started entering senior developmental ITF tournaments in the spring. Success arrived when she won two smaller ITF $10,000 tournaments in Bucharest (1 & 3) in April–May, against Elena Bogdan and then against Stéphanie Vongsouthi.
At the main ITF $50,000 tournament in Bucharest (2) in May, Halep eliminated former Roland Garros quarterfinalist Sesil Karatantcheva in the first round, before losing in the quarterfinals to fellow countrywoman Sorana Cîrstea in three sets. That was followed in June by a victory at the ITF $25,000 tournament in Sweden at Kristinehamn, by defeating the 5th seeded Anne Schaefer in the final.
She continued to play on the ITF circuit for the entirety of 2009, while also entering qualifying for main WTA tournaments at Paris Indoors in February and Roland Garros in May, losing in the 2nd round each time.
In April and May she continued her success. First, at the ITF $50,000 tournament in Makarska, Halep began her campaign with wins over Ana Vrljić of Croatia and an upset victory over Ksenia Pervak. She defeated Anne Schäfer, without dropping a game, and beat second seeded Arantxa Rus to advance to the final. However, Halep fell to the top seed Tatjana Malek in three sets. She then reached the quarterfinals at the Bucharest ITF $100,000 tournament, losing to Andrea Petkovic.
Making her first attempt to qualify for a senior Grand Slam tournament at Roland Garros, she defeated 17th seed Michaëlla Krajicek in her first match, but fell to Vitalia Diatchenko, in three sets in the following round.
In August, Halep won the ITF $25,000 tournament in Maribor, defeating top seed Katalin Marosi in the final in two sets. She also made the semifinals of the indoors ITF $50,000 tournament in Minsk, Belarus and ITF $25,000 tournament in Opole, Poland in November.
At almost 18 years old, Halep decided that her large breasts were interfering with her tennis and underwent a breast reduction surgical procedure to reduce her bust size; she later explained the decision, stating, "It's the weight that troubles me. My ability to react quickly; my breasts make me uncomfortable when I play. I don’t like them in my everyday life, either. I would have gone for surgery even if I hadn’t been a sportswoman." She also experienced back pain. After the surgery, she moved up constantly in the world rankings, reaching world No. 2 in 2014.
In January Halep entered the Australian Open, but lost to Stéphanie Foretz of France in the first round of qualifying. She was ranked 166 in the world as of April 5th 2010. Her breakthrough on the WTA tour occurred during the 2010 Andalucia Tennis Experience on the clay courts of Marbella, Spain. As a qualifier, she advanced to the quarterfinals with wins over world No. 70 Iveta Benešová and world No. 36 Sorana Cîrstea. She then put up a fight against world No. 16 Flavia Pennetta, but was eventually beaten by the No. 2 seed. Halep then qualified for the 2010 Barcelona Ladies Open by winning 3 matches, but was defeated in the first round of the main draw by Carla Suárez Navarro. Halep's form continued into the 2010 Grand Prix SAR La Princesse Lalla Meryem in Fes. Seeded first in the qualifying round, she qualified by defeating Nathalie Viérin and Estrella Cabeza Candela. In the first round she defeated No. 8 seed Lucie Hradecká in two sets. In the second round she defeated Olga Savchuk before a big upset in the quarterfinals, where she defeated No. 2 seed and former top 10 player Patty Schnyder in straight sets. In the semifinal she defeated Renata Voráčová to advance to her first WTA Tour Tournament final. But she lost to Voráčová's Czech compatriot Iveta Benešová in the final.
In May 2010 Halep qualified for her first ever Grand Slam main draw, at French Open, defeating Bethanie Mattek-Sands in the final round of qualifying. She was defeated in two sets in the first round by seventh seed and eventual finalist Samantha Stosur. In August 2010, Halep qualifed for the main draw of the US Open where she faced Jelena Janković in the first round. Halep had a chance to win over Janković, but was broken while serving for the match at 5–4 in the third. In the end, Janković won in three sets.
In January of 2011, she reached the quarterfinals in the 2011 ASB Classic defeating Ayumi Morita and Elena Vesnina, but losing to the second seed, Yanina Wickmayer. Halep would go then to the 2011 Moorilla Hobart International but she would lose in the third qualifying round, in a decisive set against Magdaléna Rybáriková. At the 2011 Australian Open, Halep qualified for the first time in her career in the third round of a tennis Grand Slam on seniors, beating the 24th seed Alisa Kleybanova before losing in straight sets to the 12th seed Agnieszka Radwańska and not progressing to the fourth round. In April at the 2010 Grand Prix SAR La Princesse Lalla Meryem, she repeated her prior year's accomplishment of reaching the finals but lost to Alberta Brianti in straight sets.
At the 2011 Estoril Open, she was defeated in the first round by the eventual champion Anabel Medina Garrigues in two tiebreaks. At the 2011 French Open, Halep beat Alla Kudryavtseva, then lost to 8th seed Samantha Stosur in the second round. In the 2011 Wimbledon Championships, Halep defeated Bojana Jovanovski before falling to 7th seed Serena Williams in three sets in the second round. For the 2011 BCR Open Romania Ladies, Halep was top seeded and progressed to the semifinals, defeating Maša Zec Peškirič, Lenka Juríková and Alexandra Cadanţu en route. However, she lost to Laura Pous Tió in the semifinals.
Halep qualified for the main draw at the 2011 Rogers Cup in Toronto but drew 12th-seeded (and 15th-ranked) Svetlana Kuznetsova as her first opponent. After dropping the first set, Halep came back to win in a 2:14 long match that saw Kuznetsova make 50 unforced errors. It was Halep's first victory over a top-20 ranked player. She lost to Lucie Šafářová in the second round.
At the 2011 US Open, Halep was placed in the main draw and faced Li Na in the first round. Despite playing with an ankle sprain she had suffered in Toronto earlier in the month, Halep defeated the sixth-seeded Li in a match that saw Li make 54 unforced errors to Halep's 19. It was Halep's first win over a top-10 ranked player. She lost in the second round to Carla Suárez Navarro in three sets.
In October at the BGL Luxembourg Open, Halep faced Kimiko Date-Krumm in the first round and defeated the former fourth-ranked player in straight sets. She fell in the second round to Anastasija Sevastova
Halep lost in the first round of the 2012 Australian Open after making the quarterfinals at Hobart. She then made it to the third round of the 2012 Indian Wells Masters and the 2012 Miami Masters. Halep then went on to make the quarterfinals in Barcelona and the semifinals at Fes. She was beaten in Madrid and Rome by Venus Williams in the first round of both tournaments.
Halep played at the 2012 Brussels Open in a tune up for the 2012 French Open. She shocked former world No. 1 Jelena Janković in the first round, and rallied against No. 4 seed Dominika Cibulková in the quarterfinals from a set down to advance to the semifinals of the WTA Premier event.
Halep began the year as the Romanian No. 2, ranked No. 47 in the world, 20 places behind Sorana Cîrstea. Her first three tournaments, ASB Classic, Hobart International and Australian Open, ended in defeats. Her first major tournament breakthrough came at the Internazionali BNL d'Italia in May, gaining three of the biggest victories of her career. Halep defeated two-time Grand Slam champion Svetlana Kuznetsova, world No. 4 Agnieszka Radwańska, and two-time tournament champion and former world No. 1 Jelena Janković (but saved 2 match points) to reach the semifinals, where she was defeated soundly by eventual champion Serena Williams in straight sets. She later said that "What changed was that I allowed myself to be relaxed on the court by taking the pressure off. I told myself to enjoy it and play with pleasure." At the French Open, Halep suffered her second successive first-round exit at a Grand Slam, falling to Carla Suárez Navarro, despite taking the first set comfortably. She rebounded well, however, going on to win her first two WTA titles back-to-back, first at the Nürnberger Versicherungscup in June, where she defeated Andrea Petkovic in the final, and then at the Topshelf Open, where she defeated world No. 11 Roberta Vinci with the loss of just one game in the second round, before defeating Kirsten Flipkens in the final. She became the first Romanian tennis player to win back-to-back tournaments on different surfaces. She claimed her first Grand Slam match win of the year at Wimbledon, defeating Olga Govortsova of Belarus, before falling to Li Na in three sets. After Wimbledon, in July, Halep entered the top-30 rankings for the first time.
Following the grass-court season, Halep went on to win her third title of the year, at the Budapest Grand Prix, where she defeated Sesil Karatantcheva, Ágnes Bukta, Tímea Babos, and fellow Romanian Alexandra Cadanțu en route to her third final of the year. She defeated Austrian Yvonne Meusburger in three sets to win her third WTA title. In the second round of Cincinnati, Halep beat Marion Bartoli in the second round in what was Bartoli's last match of her career. She then beat Samantha Stosur to reach the quarterfinals, where she once again lost to Serena Williams. She won her fourth WTA title, and first in a Premier level tournament, at the New Haven Open, defeating Petra Kvitová in the final in straight sets, which meant she entered the top-20 for the first time, at No. 19. At the US Open, Halep reached the fourth round of a Grand Slam for the first time in her career, where she ultimately lost to Italian Flavia Pennetta in two sets. She then went on to win her fifth title of the year, and her second at a Premier event, beating Samantha Stosur in the final of the Kremlin Cup. As a result of her highly successful summer, Halep became the only player of the year to win titles on clay, grass, hard, and indoor courts, as well as the second most successful player behind Serena Williams in terms of number of titles won. In November, Halep defeated former world No. 1 Ana Ivanovic to reach the final of the WTA Tournament of Champions, her ninth career final and sixth of the year. She defeated Samantha Stosur in three sets for her sixth WTA title of the season. She finished her breakthrough year ranked No. 11 in the world.
On 21 November 2013, she won the award WTA's Most Improved Player Of The Year for 2013. In December 2013, she was also named ESPN Center Court's 2013 Most Improved Player.
Halep began the year at the Sydney International in January, where she was the number 7 seed in a draw that contained 6 of the WTA's top 10, however was knocked out in her opening match against up and coming American Madison Keys, her first loss since September.
She then headed to Melbourne for the Australian Open, where she was the number 11 seed. In her opening match she faced qualifier Katarzyna Piter, defeating the Pole in 54 minutes, dropping just one game throughout the whole match. She next faced the American Varvara Lepchenko where she dropped the first set, but easily won the next two sets. In the third round, she defeated the qualifier Zarina Diyas in two sets, setting up a fourth round meeting with Jelena Janković. Halep defeated the former number one in the world in three sets and qualified for the first time in her career in the quarterfinals of a Grand Slam. Halep then lost to eventual finalist Dominika Cibulková. With the points gained at the Australian Open, she moved to number 10 in the WTA Rankings, becoming only the fourth Romanian player to enter the Top 10, after Mariana Simionescu, Virginia Ruzici and Irina Spîrlea.
On 16 February 2014, Halep competed in the final of the Qatar Open, defeating Angelique Kerber in straight sets to win her first ever Premier 5 tournament. Halep described it as "one of the best moments of my life". Then in March, as a result of defeating Casey Dellacqua at the BNP Paribas Open quarterfinals, she rose to number 5 in the world, becoming the highest-ranked Romanian in the history of the WTA.
In May, Halep reached her first WTA Premier Mandatory final at the Mutua Madrid Open, but after winning the first set for the loss of only one game, she lost to eighth seed Maria Sharapova in three sets. Her run to the final included wins over former Grand Slam champions Ana Ivanovic and Petra Kvitová in the quarterfinals and semifinals respectively. Despite having to withdraw from the Internazionali BNL d'Italia after her second round win due to injury, Halep entered the top four in the rankings for the first time in the week starting 19 May 2014.
Halep entered the French Open as the number 4 seed, and dropped just 11 games in her opening three rounds against Alisa Kleybanova, Heather Watson and María Teresa Torró Flor respectively. After defeating Sloane Stephens in the fourth round, Halep reached her second consecutive Grand Slam quarterfinal, where she defeated former champion Svetlana Kuznetsova. She reached her first Major final by defeating 28th seeded German Andrea Petkovic in the semifinals, which ensured that Halep would be world No. 3 and the first Romanian since Virginia Ruzici in 1980 to reach a Major final. Halep is also the first player since Martina Hingis in the 1997 Australian Open to reach her first Grand Slam final without losing a set. In the final, Halep lost to Maria Sharapova in a match lasting over three hours, in a re-match of the Madrid Open final staged a few weeks prior.
At Wimbledon, Halep made it through her first four rounds with relative ease, dropping just one set on her way to a third consecutive Grand Slam quarterfinal. She then defeated previous year's finalist Sabine Lisicki in straight sets to reach the semifinals at Wimbledon for the first time, where she faced Canadian Eugenie Bouchard for a place in the final. Halep lost in straight sets, an ankle injury suffered in the first set proving to be her downfall. Halep then returned to her home of Romania to play the inaugural 2014 Bucharest Open, winning the final in straight sets against Roberta Vinci to clinch her second title of the year.
On 11 August, Halep rose to second in the world rankings, overtaking Li Na; this was despite her non-participation at the Rogers Cup, where Li was a semifinalist last year but was forced to withdraw from the tournament this year due to a knee injury. Halep returned at Cincinnati, where after being given a first round bye as the second seed, she defeated Kirsten Flipkens and Lucie Šafářová in straight sets, before losing for a fifth time (and third this year) to Maria Sharapova in the quarterfinals. At the US Open, Halep the 2nd seed reached the third round where she was upset by the resurgent Mirjana Lučić-Baroni in straight sets.
Halep won her first ever WTA Finals match, beating fellow Finals debutante Eugenie Bouchard in straight sets. On 22 October 2014, Halep stunned two-time defending champion Serena Williams. Williams's two games won equaled her career worst; the last time Williams managed to win just two games in a WTA Tour or Grand Slam match was in 1998 when she was just 16 years old. Halep could have eliminated Williams from the tournament had she lost her final round-robin match to Ana Ivanovic in straight sets; however, Halep chose to play to win the match and ended up losing in three sets. Despite the defeat, Halep won her group and secured an appearance in the semifinals. She advanced to the final by beating Agnieszka Radwańska in straight sets. In the final match, she once again faced Williams, but this time lost in straight sets.
Halep started the year ranked 3rd. In the first half of January 2015, Halep played at the Shenzhen Open where she was the top seed, winning her ninth WTA title against No. 47 Timea Bacsinszky. Halep then pulled out of Sydney due to illness.
Next, Halep played at the Australian Open, where she was seeded 3rd. Halep secured keeping her No. 3 ranking after winning her first four matches against unseeded players Karin Knapp, Jarmila Gajdošová, Bethanie Mattek-Sands and Yanina Wickmayer, all in straight sets. However, she lost against the 10th seed Ekaterina Makarova in the quarterfinals, in two sets.
In February, Halep won her tenth WTA title (and her second Premier 5 tournament) in the hard court event at Dubai, where she beat Ekaterina Makarova in the quarterfinals, Caroline Wozniacki in the semifinals and Karolína Plíšková in the final. With this title win, she regained her No. 3 WTA ranking. However, Halep pulled out of the following event, Doha, with a rib injury.
In March, Halep played at the Indian Wells Masters despite learning of a cousin's suicide earlier in the week. She won three-set matches against Daria Gavrilova and Varvara Lepchenko before beating Karolína Plíšková in two tight sets in the fourth round. Halep then beat Carla Suárez Navarro in three sets to reach the semifinals of the event for the second straight year. She made it to the final after world No. 1 Serena Williams withdrew with a right knee injury. Halep won the final match against the 18th seed Jelena Janković in three sets to claim her biggest career title to date and take over the lead in the Road to Singapore standings. In the following tournament, Halep did well again in Miami. She reached the semifinals, where she lost in a tough match to eventual winner, No. 1 Serena Williams.
In April in Stuttgart, Halep reached the semifinals after defeating Garbiñe Muguruza and Sara Errani, but she lost in a three-hour match to Caroline Wozniacki. With this result, she climbed up again to No. 2 in the WTA rankings.
In May, Halep lost in the 1st round in Madrid to Alizé Cornet, but then in the Italian Open, she had a good run, losing only seven games in the first three matches. She beat Alison Riske, Venus Williams and fellow countrywoman Alexandra Dulgheru. However, in the semifinals she lost to 4th seed Carla Suárez Navarro in a long three set match. Due to Maria Sharapova reaching the final (and eventually winning it), Halep dropped to No. 3 in the WTA rankings. Halep's next tournament was the French Open where she entered as the 3rd seed. She was unable to back up her final result from the previous year despite being one of the favorites for the title. Halep was overpowered and lost in the second round in straight sets for the second time in the last 3 majors to the hard hitting Mirjana Lučić-Baroni.
During the grass season, she reached the quarterfinals in Birmingham. At Wimbledon, she was one of six seeded female players to be knocked out in the first round, losing to Jana Čepelová in three sets. During her match against Čepelová, Halep suffered a blister on the middle toe of her left foot. After Wimbledon, Halep took a couple of weeks off to regroup and make her game stronger again.
In Toronto, Halep resumed her good game, winning against Jelena Janković, Angelique Kerber, Agnieszka Radwańska and Sara Errani, thus reaching the final to play against rising star Belinda Bencic (who had ousted five slam finalists en route to the finals). After two exhausting tiebreaks, Halep retired due to a leg injury and the extreme heat in the final set. In Cincinnati, Halep continued her good form, defeating Kristina Mladenovic, Andrea Petkovic, Anastasia Pavlyuchenkova and Jelena Janković en route to her fifth final of the year, where she was beaten by world No. 1 Serena Williams. With this result, Halep again climbed up to world No. 2. Also, she became the second player to qualify for the Singapore 2015 WTA Finals, after Serena Williams.
As the No. 2 seed at the 2015 US Open, Halep reached the semifinals (her best performance to date at this Grand Slam, and her best Grand Slam result in 2015) after defeating in straight sets Marina Erakovic, Kateryna Bondarenko and Shelby Rogers, then in three sets Sabine Lisicki and former No. 1 Victoria Azarenka. In the semis, she lost in two sets to eventual winner Flavia Pennetta. She also played for the first time in the mixed doubles tournament, paired with countryman Horia Tecău. They won two matches, but withdrew before the quarterfinals.
Halep resumed her season in Guangzhou, where she was the top seed. She won in two sets against qualifier Petra Martić and Tímea Babos, but lost in quarterfinals to young Denisa Allertova, who was apparently just training for the next tournament in the hot and humid climate of South China. Then, Halep was also seeded No. 1 in Wuhan, a Premier 5 tournament. Halep easily defeated Anastasia Pavlyuchenkova in the second round, but then lost a thrilling match to Johanna Konta (after leading 5–1 in the final set). In Beijing, Halep had to retire during the first set of her opener, due to injury.
With world No. 1 Serena Williams not playing in Singapore, Halep was seeded No. 1 in the 2015 WTA Finals, and she started very well with a victory over recent US Open winner Flavia Pennetta. After losing in two sets to both Maria Sharapova and Agnieszka Radwańska, she failed to qualify further. However, she kept her No. 2 position in the WTA rankings, ending the season with her best ever year-end ranking. She won three titles and had a win-loss record of 40–10.
After missing the Brisbane International due to an achilles injury, Halep started the season in the Sydney tournament where she reached the semifinals by defeating Caroline Garcia and Karolína Plíšková, but she lost to Svetlana Kuznetsova in three sets. Then, at the Australian Open where she was seeded second, she was stunned in the first round, losing to qualifier Shuai Zhang, who had not won a Grand Slam match in her previous 14 attempts.
Halep later revealed through a social media statement that she was struggling with an ongoing nose issue. In the same statement, she announced a surgery to fix the issue, having to withdraw from the Dubai Tennis Championships, where she was the defending champion, and the Qatar Open. Halep would also miss Romania's Fed Cup tie; however, she postponed her surgery and stated in early February that she was able to join the squad for their matches against Czech Republic, as well as play in both Doha and Dubai, saying she had "started to play good tennis". In the Fed Cup, she lost her first match to Karolína Plíšková (losing to her for the first time in four meetings), but rebounded to defeat Petra Kvitová for the third time in as many meetings in her second match; it was, however, not enough for Romania to advance to the semifinals. Then, in Dubai she was defeated by former world number one Ana Ivanovic in her first match. She suffered yet another opening round loss to Elena Vesnina at the Qatar Open a week after her Dubai defeat, dropping two spots to world No. 5.
Being the defending champion at the BNP Paribas Open, Halep was seeded 5th and was given a bye into the second round. There, she faced Vania King and won in just 56 minutes. Then, in the third round, she faced 30th seed Ekaterina Makarova and won in straight sets. In the fourth round, after being down 3–1 in the first set, Halep won six straight games until Barbora Strýcová retired. In the quarterfinals, Halep faced world No. 1 Serena Williams, but lost in straight sets.
In the Miami Open, defending semifinal points from the previous year, she faced 18-year-old Russian Daria Kasatkina in the second round after receiving a bye, winning in straight sets. She then defeated Julia Görges and Heather Watson in straight sets, reaching the quarterfinals for the second year running. However, she lost to Timea Bacsinszky despite winning the first set. Since Victoria Azarenka went on to win the title, Halep fell out of the top 5 for the first time since May 2014 when she made her top 5 debut.
Having taken a short break, Halep returned to action after being named in Romania's team for the Fed Cup World Group Play-offs. She defeated Andrea Petkovic in her first rubber despite failing to serve out the match twice. In her second match, hampered by injuries, Halep lost to Angelique Kerber, winning only four games, which was her first defeat to the German in four career meetings. Romania ultimately lost to Germany 1–4 and fell to World Group II for 2017.
She began her clay court campaign by participating in the Stuttgart Open. After receiving a first round bye, she lost to German qualifier and eventual finalist Laura Siegemund, winning only three games. This loss was her worst since the 2014 WTA Finals, where she lost to Serena Williams in the final, winning only three games as well. At the Mutua Madrid Open, Halep defeated Misaki Doi, Karin Knapp, Timea Bacsinszky, fellow Romanian Irina Camelia-Begu and Samantha Stosur en route to the final. She then beat Dominika Cibulková in straight sets and ensured her first title (and second Premier Mandatory of her career) of 2016. Due to Halep's title in Madrid, she returned to the top five of the WTA rankings at No. 5. However, she didn't keep her winning streak, as it ended at the hands of Daria Gavrilova at the Italian Open.
At the French Open, Halep defeated Nao Hibino (dropping only two games in the match), Zarina Diyas and Naomi Osaka. She was then knocked out of the tournament in a rain-affected match against Samantha Stosur in the round of 16.
She was aiming to start her grass-court season in Birmingham but pulled out due to injury. Halep reached the quartefinals of Wimbledon after straight-set victories over Anna Karolína Schmiedlová, former French Open champion Francesca Schiavone, Kiki Bertens and a three-set win over Madison Keys. She then lost to Angelique Kerber.
In mid-July, Halep pulled out of the 2016 Summer Olympics due to concerns about the Zika virus. Then in her home country, she won the Bucharest tournament for the second time. She continued her form during the 2016 Rogers Cup. She defeated Svetlana Kuznetsova in the quarterfinals and then avenged her Wimbledon quarterfinal loss by beating Angelique Kerber in the semifinals. By advancing to the final, Halep returned to world No. 3 in WTA ranking. In the final she defeated Madison Keys in straight sets to win her third title of the season. She also made here her best doubles result so far, reaching the final, paired to Monica Niculescu. Her next tournament was the Western & Southern Open, where she defeated Annika Beck, Daria Gavrilova and Agnieszka Radwanska before losing to Kerber in the semis.
In the 2016 US Open Halep beat Kirsten Flipkens in the first round, Lucie Šafářová in the second, Timea Babos in the third, and Carla Suarez Navarro in the round of sixteen. She then played an epic match against Serena Williams, with a rare comeback in set 2, but eventually she lost in three sets.
In Wuhan, Halep played solid, reaching the semifinals without losing a set, but she lost to very in form and eventually champion Petra Kvitová. She became the third player qualified for Singapore with this performance, after Kerber and Serena.
In Beijing, which would be her last tournament of the year before WTA Finals, Halep received a bye into the second round, as a Wuhan semifinalist, and she debuted with a straight victory against Yanina Wickmayer, before falling to Shuai Zhang for the second time this year. She ended her year with a disappointing round-robin elimination in the WTA Finals.
Simona Halep started the season at the Shenzhen tournament where she lost in the second round to Kateřina Siniaková after beating Jelena Jankovic. Halep's next tournament was the Australian Open where she lost in the first round to Shelby Rogers. It was her second first-round exit in a row. Halep later stated she was struggling with a left knee pain.
Halep's next tournament was 2017 St. Petersburg Ladies' Trophy. Simona was the first seed of the tournament, so she received a bye into the second round. In the second round, she beat Ana Konjuh in straight sets but was forced to withdraw from her quarterfinal against the wildcard Natalia Vikhlyantseva after her ongoing left knee injury. She also missed Romania's Fed Cup tie against Belgium. At the BNP Paribas Open, Halep received a first round-bye and beat Donna Vekic before losing to Kristina Mladenovic for the third time in her career. She then played at the Miami Open where, after another first round-bye, she beat Naomi Osaka, Anett Kontaveit and Samantha Stosur en route to the quarterfinals, where she lost to eventual champion Johanna Konta in three sets, having served for the match in the second set. Prior to the clay season, Halep joined Romania's Fed Cup team for their tie against Great Britain, beating Heather Watson and Johanna Konta and helping Romania win 3–2.
Halep kicked off her clay season with a run to the semifinals at the Porsche Tennis Grand Prix, beating Barbora Strýcová and Anastasija Sevastova before losing to eventual champion Laura Siegemund. She then entered the Mutua Madrid Open as the defending champion and regained the title defeating Kristýna Plíšková, Roberta Vinci, Samantha Stosur, Coco Vandeweghe (losing only two games), Anastasija Sevastova, and Kristina Mladenovic en route to the championship. Due to her title defense, Halep, who was ranked as the World No.8 during the tournament, returned to the Top 5. Halep continued her success in Rome, beating Laura Sigemund (grabbing her first win over the German), Anastasia Pavlyuchenkova, Anett Kontaveit and Kiki Bertens before losing in the three-set final to Elina Svitolina, while also sustaining an ankle injury during that match.
Halep went into the French Open as one of the favourites, seeded third. She beat Jana Čepelová, Tatjana Maria and Daria Kasatkina in straight sets in the first three rounds. In the 4th round she beat Carla Suárez Navarro for the first time on clay in six meetings in a straight sets victory. Halep then played Elina Svitolina in the quarterfinals and turned the match around (Svitolina was up a set and 5–1) to advance to her second French Open semifinal, where she beat Karolína Plíšková in three tight sets to advance to her second Grand Slam final. Her win against Plíšková ensured the return to the No. 2 spot in the world and the No. 1 spot on the Race to Singapore leader board. She then faced first time finalist Jeļena Ostapenko with the world no.1 ranking on the line. Halep was a set and 3–0 up but ended up losing the championship match in three sets.
In Eastbourne and Wimbledon she again played with the no. 1 ranking within reach, but lost each time, the latter loss coming in a thrilling encounter against Johanna Konta, with the Brit scoring yet another comeback win against Halep. She chose not to play in Bucharest the week after, to prepare for the hardcourt season, although a win would've seen her climb to the top spot in the rankings.
During the American hardcourt summer, she continued to chase the seemingly elusive no. 1 spot in Washington DC, Toronto and Cincinnati. After an impressive run of reaching the QFs at 10 consecutive tournaments, she was in need of one more win in Cincinnati to climb on the top of the WTA ladder. On August 20, she lost the Cincinnati Masters final to Muguruza, leaving her a mere 5 points behind Karolina Pliskova when the new rankings release the next day. She promised her fans to come back even stronger in the 2017 US Open.
At the 2017 US Open, Halep lost to former World No.1 Maria Sharapova in the first round on August 28.
Simona Halep's current clothing sponsor is Adidas, having previously had her apparel supplied by Lacoste and her shoes by Nike. In November 2014 she also signed a deal with Vodafone Romania for three years. As of 2016, Halep endorses Hublot watches. As of 2017, Halep is a brand ambassador for Mercedes-Benz Romania.
She was coached from an early age by Ioan Stan, a local tennis coach in Constanța. Halep has also previously been coached by Adrian Marcu, Andrei Mlendea and Firicel Tomai.
In January 2014, Simona Halep hired Belgian coach Wim Fissette, former coach of Kim Clijsters and Sabine Lisicki. At the end of the year, she chose to split with him and hired Romanian coach Victor Ioniță, with Thomas Högstedt serving as a coaching consultant for the first three tournaments of the year. In November 2015, Halep announced that Darren Cahill would be her full-time coach, starting in January 2016. She is managed by Virginia Ruzici. Her fitness coach is Teo Cercel.
Simona Halep has self-described her playing style as being "an aggressive baseliner" and "she models her game on Justine Henin". Henin herself said the following about Halep: "She has an intelligent game. There is a little something that reminds me of myself... it is offensive and aggressive."
In 2010, before her breakthrough, New York Times columnist Michael Kimmelman described her as "a scrappy player from Romania, short but with potent ground strokes and a scrambler's talent."
By 2014, Louisa Thomas of Grantland was writing with admiration that "it turns out that [Simona] is astonishingly fast. She started to think ahead during points [...] she has uncanny anticipation. She became even faster [...] her strokes became more simple: compact, beautiful, unreadable. [...] she learned to disrupt the opposition's rhythm and disguise her own. At her best, she does not play in patterns. She hits with surprising power. She covers the whole court. She hits balls with heavy power without making a sound. [...] Like Djokovic she has a talent for hitting winners from defensive positions. She is a defensive aggressor, an aggressive defender. She is becoming unclassifiable." After Halep finished runner-up in her first Grand Slam final against powerful hitter Maria Sharapova in Roland Garros in 2014, Eleanor Crooks of The Independent wrote that Halep "has a lovely fluidity of movement and superb balance that enables her to comfortably trade with more powerful players". Michael Beattie of Wimbledon.org also noticed that [Halep] "is free of the shrieks, tics and fist-pumps of her contemporaries."
In terms of tennis strategy Halep is an aggressive counterpuncher. Her very fit body and athleticism provide her with very good all-court movement and she tends to make few errors; she also uses this agility to reach the ball earlier because of her wide back swings and sliding. At the same time she likes to control the rally and can hit very effective cross-court and down-the-line flat shots, generally producing winners.