Nara has won one singles title on the WTA tour, as well as five singles and three doubles titles on the ITF tour in her career. On 18 August 2014, she reached her best singles ranking of world number 32. On 2 May 2016, she peaked at world number 109 in the doubles rankings.
Playing for Japan at the Fed Cup, Nara has a win-loss record of 6-5.
Nara began playing tennis at the age of 3. At the Esaka Tennis Center in Osaka, the budding pro player studied tennis under the tutelage of Japanese tennis luminaries Masaru Suishu and Hiroko Mochizuki. She won recognition from an early age as a tennis prodigy. In 2002, while enrolled in Kawanishi Makinodai Elementary School, Nara took second place in the All Japan Primary School Tennis Championships at the age of 10. She would go on to win that tournament in 2003.
In 2004, after entering the middle school associated with Osaka Sangyo University, Nara won the girls' singles title in the All Japan Middle School Tennis Championship. 2006 marked her debut, via sponsor recommendation, in the All Japan Tennis Championships women's singles draw; however, a first-round loss abruptly ended her tournament run. As a freshman at Osaka Sangyo's high school in 2007, Nara won the under-18 singles title at the All Japan Junior Tennis Championships.
In addition to her participation in the major events for her age group, Nara also accumulated victories each year in junior tournaments throughout Japan. She enjoyed success in doubles on the ITF Junior Circuit with partner Misaki Doi, earning entrance to the girls' doubles draw at the 2007 Wimbledon Championships. They placed second overall, becoming only the second Japanese women's doubles pair to reach the finals of a Grand Slam juniors event since Yuka Yoshida and Hiroko Mochizuki at the 1993 US Open. The Nara–Doi team went on to reach the junior doubles semifinals at the 2007 US Open and Wimbledon 2008, in addition to strong performances at smaller tournaments.
Nara also enjoyed success in singles. In 2007, she became the first Japanese woman to win the Osaka Mayor's Cup since Ryōko Fuda in 2002. Also that year, she made her second appearance, again by sponsor recommendation, in the All Japan Tennis Championships. In the second round, she defeated defending champion and 5th seed Erika Takao in straight sets, in the third round, she toppled 11th seed Tomoko Yonemura in three sets, and in the quarterfinals she lost to Junri Namigata. Nara teamed again with Misaki Doi in doubles, reaching the second round in her tournament doubles debut. The next year, Nara partnered with Kimiko Date-Krumm to win the Kangaroo Cup in Gifu and the title in the open tournament at Hamanako. Nara reached the third round of the 2008 US Open Girls' Singles tournament, where she lost to Kristina Mladenovic.
Nara turned pro in April 2009, winning the All Japan Tennis Championships that same year. She advanced to the main draw of a Grand Slam tournament for the first time at the 2010 French Open with a three set win over Monica Niculescu in the qualifiers. At four hours and 42 minutes, it was said to be the longest women's Grand Slam qualifier or main draw match in history. She would go on to lose her first round match to Arantxa Parra Santonja. She also qualified for Wimbledon, and won her first Grand Slam main draw singles match in two sets over Mariana Duque Mariño. She fell to Li Na in the second round.
Nara failed to gain entrance to the four Grand Slam tournaments in 2011, falling in the qualifiers each time. July marked Nara's first appearance representing Japan in Fed Cup competition; she notched a win in doubles with partner Rika Fujiwara in the playoffs against Argentina.
Although she was again unable to pass the qualifying rounds of the year's Grand Slam events, Nara bested Polona Hercog and Eleni Daniilidou to qualify for the Toray Pan Pacific Open in Tokyo. She was defeated in the first round by Urszula Radwańska.
Nara won three qualifying matches to enter the main draw of the 2013 US Open, winning her first-round match against Romanian Alexandra Cadanțu. She advanced to the third round of a Grand Slam for the first time with a straight set upset victory over 19th-seeded Sorana Cîrstea, also of Romania. She lost to Jelena Janković in the third round. After four early exits in Tashkent, Guangzhou, Tokyo and Beijing Nara regained some form in her home city at the Rakuten Japan Open Tennis Championships. Nara would make it to the semi-finals of the tournament but was ousted by Eugenie Bouchard, losing in straight sets.
Nara started the year with the ASB Classic in New Zealand, where she made it to the quarterfinals, losing there to second seed Ana Ivanovic. Next up was the Australian Open, where she lost to eighth seeded Jelena Janković in the third round in straight sets. In early February, Nara competed in Fed Cup competition for Japan against Argentina in Buenos Aires, Argentina. She lost the opening singles match to María Irigoyen in three sets, and also lost the reverse singles to Paula Ormaechea in straight sets. Later the same month, Nara won her first WTA title at the Rio Open. She beat top seeded Klára Zakopalová in three sets in the final. The win helped her break into the top 50 at no. 48. At the Indian Wells Masters, Nara lost in the second round to Simona Halep in straight sets. At the Miami Masters, she lost to fourth-seeded Maria Sharapova in straight sets in the second round.
In April, Nara again played Fed Cup, this time against the Netherlands. She won the opening singles match against Arantxa Rus in three sets, but lost to Kiki Bertens in three sets in the reverse singles match. Nara's next match was a disappointing first-round loss at the Portugal Open to qualifier Irina-Camelia Begu in the first round. Another first-round loss came in May against Peng Shuai at the Madrid Open. In a rematch from the Fed Cup World II tie, Nara again lost to lucky loser Paula Ormaechea in her first-round match at the Italian Open. As the sixth seed, Nara lost to Yaroslava Shvedova at the Nürnberger Versicherungscup in the second round. Lost to sixth-seed Jelena Janković in the second round at the French Open. Entered the doubles competition with Anna Karolína Schmiedlová losing in the first round to Chan Hao-ching & Chan Yung-jan.
In June, Nara started the grass season at the Aegon Classic For the second consecutive year, she lost to wildcard Johanna Konta in the first round. Lost to Elina Svitolina in the first round at the Topshelf Open. Played doubles with Annika Beck losing to Andreja Klepač & María Teresa Torró Flor in the first round. Lost to Venus Williams in the second round at Wimbledon. Partnering again with Annika Beck in doubles, lost to Vera Dushevina & Chanelle Scheepers in the first round.
In July, Nara as the sixth seed reached the quarterfinals losing to second-seeded Roberta Vinci at the İstanbul Cup. Was seeded fourth but lost to Francesca Schiavone in first round at the Baku Cup. Lost in the final against sixth-seeded Svetlana Kuznetsova at the Citi Open. Entered the doubles partnering with Hiroko Kuwata losing to the second-seeded team of Shuko Aoyama & Gabriela Dabrowski in the finals. Was scheduled to play in the Rogers Cup but withdrew with a hip injury. Lost to Agnieszka Radwańska in the second round of the Western & Southern Open. Playing in her last tournament before the US Open, lost to Samantha Stosur at the Connecticut Open in opening round. Nara as the 31st seed playing at the US Open suffered a disappointing three-set lost to Belinda Bencic in the second round. Also she entered the doubles with Shuko Aoyama losing to Jelena Janković & Klára Koukalová in the first round.
In September, Nara withdrew from the Hong Kong Tennis Open. Lost to eighth-seeded Carla Suárez Navarro in the first round at the Toray Pan Pacific Open. Entered again with Shuko Aoyama in the doubles losing to the second-seeded team of Raquel Kops-Jones & Abigail Spears in the first round. Suffered another first round loss at the Wuhan Open to Svetlana Kuznetsova. Unseeded and playing singles only at the China Open, advanced to the second round losing again to Kuznetsova. Was scheduled to be the fourth seed at the Japan Women's Open but withdrew with a respiratory illness.
Nara is coached by Takahiro Terachi. She uses a Srixon racquet and Dunlop Sport shoes, and prefers to play on hard courts. Her most admired player is Justine Henin. In her free time, Nara enjoys reading books, listening to music, and attending motorcycle races.
Kurumi Nara rarely wins points outright. Instead, she plays a patient game and tends to edge into points, gradually increasing the angle and/or power of her shots and prefers a punishing forehand or volley to close the point out. Her patience is also reflected in her serve, which (especially for her size) has quite a high ball toss. Her serve lacks the punch of players like Serena Williams or Maria Sharapova, but depends on placement and spin. Her short stature has definitely shaped her play style which, while aggressive, does not emphasize power, but more swinging the momentum in her favour and finishing the point off. Her strong forehand is her main weapon.