King's parents moved to the United States from Taiwan in 1982. She is the youngest of four children. Her brother Phillip was a two-time All-American at Duke University and two-time US junior champion. Vania is a graduate of Long Beach Poly High School in California.
In 2006 King won her only WTA singles title at the PTT Bangkok Open, a Tier III tournament. She defeated Tamarine Tanasugarn in the final. On November 6, 2006, King achieved her career-high singles ranking of world no. 50.
In 2009, she reached the mixed doubles final at the French Open alongside Brazilian player Marcelo Melo, losing to top seeds Liezel Huber/Bob Bryan.
King lost in the second round of the 2009 Wimbledon Championships to no. 15 Flavia Pennetta. She played in the ladies doubles with Anna-Lena Grönefeld, losing in the quarterfinals to eventual champions Venus and Serena Williams.
At the 2009 U.S. Open, King was granted a wild card and had her best singles Grand Slam performance. She was defeated in the third round by world no. 22 Daniela Hantuchová.
King began the year ranked no. 80 in the world at the Brisbane International. She reached the second round of the singles tournament, losing to Andrea Petkovic. In doubles, she partnered with Anna-Lena Grönefeld and lost in the first round to Timea Bacsinszky and Tathiana Garbin. King and Grönefeld fared better at the Medibank International in Sydney, where they were seeded fourth. They lost in the semifinals to Garbin and Nadia Petrova. In the singles tournament, King failed to qualify, losing in the first round of the qualifying tournament to top seed Ágnes Szávay, who went on to defeat Jelena Janković in the first round of the tournament.
At the 2010 Australian Open, King lost in the second round to Roberta Vinci. In doubles, she partnered with Grönefeld again and entered the tournament seeded 14th. They lost in the second round to Svetlana Kuznetsova and Victoria Azarenka.
King's next major tournament was the Memphis international in mid-February. She entered the singles tournament seeded seventh and lost in the second round to Sofia Arvidsson of Sweden. In the doubles tournament, she and partner Michaëlla Krajicek were seeded third and won the tournament without dropping a set, defeating Bethanie Mattek-Sands and Shaughnessy in the final.
King then traveled to the Monterrey Open. In doubles, she reunited with Groenefeld and reached the finals as the top seed, falling to second-seeded Benešová/Záhlavová. In singles, she lost in the quarterfinals to second seed Daniela Hantuchová.
At the BNP Paribas tournament in Indian Wells, King lost in the second round to second seed Caroline Wozniacki. She did not enter the doubles tournament. King fared better in the Sony Ericsson Open in Miami later that month. She partnered with Julie Coin and reached the quarterfinals of the doubles tournament, before losing to third seeds Petrova and Samantha Stosur, who went on to become the runners-up.
King's next Premier was the Family Circle Cup in Charleston, where she reunited with Krajicek and reached the final, before falling to top seeds Liezel Huber and Petrova. In singles, she lost to Petrova in the second round.
At the Madrid Masters, King paired with Chuang Chia-jung for the first time for the doubles tournament. They defeated fourth seeds Huber and Anabel Medina Garrigues, before falling in the quarterfinals to Pe'er and Francesca Schiavone. In singles, King lost in the first round to Karolina Šprem.
King then entered the Strasbourg International. In the doubles tournament, she partnered with Alizé Cornet and won the tournament after an injury to Lucie Hradecká forced top seeds Hradecká/Chuang to retire in the second round. King/Cornet defeated second seeds Rodionova/Kudryavtseva in the final for her 10th tour doubles title. In singles, King defeated second seed Elena Vesnina in the first round and reached the semifinals, before falling to Kristina Barrois.
At the 2010 French Open, she lost in the first round to Bethanie Mattek-Sands. She entered the mixed doubles tournament with Christopher Kas, reaching the semifinals, before falling to Shvedova and Julian Knowle. In women's doubles, she reunited with Michaëlla Krajicek and reached the second round, losing to fourth-seeded Petrova and Stosur.
At Wimbledon, King won the 2010 ladies' doubles title in straight sets with Kazakh partner Yaroslava Shvedova. They defeated Russians Elena Vesnina and Vera Zvonareva in the final.
At the 2010 US Open, King and Shvedova won their second Grand Slam doubles title, defeating the second-seeded pair Liezel Huber and Nadia Petrova in a rain-delayed final.
At the Stanford Classic, Vania lost to Romanian Sorana Cîrstea.
King and Shvedova made the finals of the US Open, losing to Liezel Huber and Lisa Raymond.
King made it to the finals of five other WTA tournaments in the course of the year, one in Monterrey with Anna-Lena Grönefeld and in Rome, Cincinnati, Osaka, and Moscow with Shvedova. She and Shvedova won the events in Cincinnati in August and Moscow in October.
King reached the third round of the Australian Open at the start of the year, losing to Ana Ivanovic. She had defeated Kateryna Bondarenko in the first round.
She reached the second round of the Mercury Insurance Open in Carlsbad in July, losing to Marion Bartoli.
In doubles, she reached the final in Stanford with Jarmila Gajdošová and in Carlsbad with Nadia Petrova, but lost to Marina Erakovic and Heather Watson in Stanford and to Americans Raquel Kops-Jones and Abigail Spears in Carlsbad.
In singles action in 2013, King lost in the Guangzhou final to Shuai Zhang. King lost in the second round of the French Open and in the first round of the other three Slans. In doubles that year, her best finish was a finals loss in Guangzhou.
In doubles, King made the second round at the Australian Open partnering Galina Voskoboeva. They lost to the Czech/Dutch pair of Lucie Hradecká and Michaëlla Krajicek.
She partnered with Barbora Strýcová in Florianópolis, and they made it to the semifinals before being defeated by Anabel Medina Garrigues and Yaroslava Shvedova. She was eliminated in the first round in Indian Wells, and the second round in Miami, but made it to the final in Bogotá, partnering Chanelle Scheepers of South Africa.
Partnering Jie Zheng of China, she made a quarterfinal appearance in Madrid, losing to Sara Errani and Roberta Vinci. Then followed a series of first-round losses, including Roland Garros and Wimbledon.
She had some success in the late summer, making the quarterfinals in Washington, D.C. partnering Taylor Townsend and the third round at the US Open partnering Lisa Raymond.
In singles, she made the semifinals in Shenzhen, but had to concede a walkover. She made a first-round exit at the Australian Open at the hands of Carla Suárez Navarro. At the Pattaya Open, she was defeated by Elena Vesnina in the first round. A series of first-round defeats followed in Rio de Janeiro, Florianópolis, and Indian Wells.
She made the second round in Miami and Charleston, but it was not until April in Bogotá that she found some form and made it to the semifinals. She went down in the first round in both Roland Garros and Wimbledon, but she did make the quarterfinals in Washington, D.C..
At the US Open, she defeated Francesca Schiavone in the first round, but lost to eventual champion Serena Williams in the second round.
King missed the first three Slams of 2015 due to injury. She lost in the first round of singles and the second round of doubles there in Flushing. The highlight of her year came on hard courts in Waco, where King and Nicole Gibbs won in November, defeating Julia Glushko and Rebecca Peterson 6-4, 6-4.
In 2017, King reunited with the doubles partner with whom she had had the most success, Yaroslava Shvedova. They made it to the semifinals in Sydney, where they lost to Sania Mirza and Barbora Strycova.
At the Australian Open, King and Shvedova advanced to the third round, where they lost to Mirjana Lucic-Baroni and Andrea Petkovic. They were stopped in the second found of Indian Wells by the Japanese-Chinese pair of Shuko Aoyama and Zhaoxuan Yang. In Miami, the went on to the quarterfinals, where they again lost to Mirz and Strycova.
KU=with Kevin Ullyett
FC=with František Čermák
MM=with Marcelo Melo
CK=with Christopher Kas
VS=with Vincent Spadea
DM=with David Martin
JK=with Jordan Kerr
HT=with Horia Tecău
DN=with Daniel Nestor
DB=with Dustin Brown
RB=with Rohan Bopanna
TB=with Tomasz Bednarek