Navratilova was born Martina Šubertová in Prague, Czechoslovakia. Her parents divorced when she was three, and her mother, an accomplished gymnast, tennis player, and ski instructor, moved the family to Řevnice. In 1962, her mother Jana married Miroslav Navrátil, who became her first tennis coach. Martina then took the name of her stepfather (adding the feminine suffix -ová), thus becoming Martina Navrátilová. Her father, Mirek (officially Miroslav Šubert), was a ski instructor.

When Navratilova was four, she was hitting a tennis ball off a concrete wall and started to play tennis regularly at age seven. In 1972, at the age of 15, Navratilova won the Czechoslovakia national tennis championship. In 1973, aged 16, she made her debut on the United States Lawn Tennis Association professional tour but did not turn professional until 1975. Although perhaps most renowned for her mastery of fast low-bouncing grass, her best early showing at majors was on the red clay at the French Open, where she would go on to reach the final six times. In 1973, she made the quarterfinals where she lost 6–7, 4–6 to Evonne Goolagong. She made the quarterfinals the next year and lost to Helga Masthoff (née Niessen), after again losing the first set in a tiebreak.

Navratilova won her first professional singles title in Orlando, Florida in 1974, at the age of 17. Upon arriving in the United States, Navratilova first lived with former Vaudeville actress, Frances Dewey Wormser, and her husband, Morton Wormser, a tennis enthusiast.

Navratilova was the runner-up at two major singles tournaments in 1975; the Australian Open (won by Goolagong) and the French Open (won by Chris Evert in three sets). After losing to Evert in the semifinals of the US Open in September, the 18-year-old Navratilova went to the offices of the Immigration and Naturalization Service in New York City and informed them that she wished to defect from Communist Czechoslovakia. Within a month, she received a green card and in 1981 became a US citizen. Also, in 1975, Navratilova teamed with world number one Evert to win the French Open women’s doubles title, Navratilova’s first major title outside of mixed doubles. They teamed again in 1976 to win the Wimbledon women’s doubles title over Billie Jean King and Bette Stove.

Navratilova won her first major singles title at Wimbledon in 1978, where she defeated Evert in three sets in the final and captured the world No. 1 ranking for the first time on the WTA computer, a position she held until Evert took it back in January 1979. Navratilova successfully defended her Wimbledon title in 1979, again beating Evert in the final in straight sets, and earned the World No. 1 ranking at the end of the year for the first time. Just before Wimbledon in 1979, Navratilova and Evert played possibly the highest scoring women’s professional match ever in the Eastbourne final, in which Evert edged Navratilova 7–5, 5–7, 13-11 after facing match points herself. In April 1981, Evert defeated Navratilova in the finals of the Women’s Tennis Association championships, held on clay at Amelia Island, 6–0, 6–0. It was Navratilova’s only professional double bagel loss (one she later avenged with a crushing 6–2, 6–0 defeat of Evert in the finals of the same Amelia Island event in 1984). It was at this point that Navratilova began working with Nancy Lieberman to improve her fitness and toughen her mental approach to better compete with Evert and fulfil her true potential. In 1981, Navratilova won her third major singles title by defeating Evert in the final of the Australian Open. Navratilova also defeated Evert to reach the final of the US Open, where she lost a third set tiebreak to Tracy Austin. Navratilova won both Wimbledon and the French Open in 1982.

In 1981, shortly after becoming a United States citizen, Navratilova gave an interview to New York Daily News sports reporter Steve Goldstein, coming out as bisexual and revealing that she had a sexual relationship with Rita Mae Brown, but asked her not to publish the article until she was ready to come out publicly. However, the New York Daily News published the article on July 30, 1981. Navratilova and Nancy Lieberman, her girlfriend at the time, gave an interview to Dallas Morning News columnist Skip Bayless, where Navratilova reiterated that she was bisexual and Lieberman identified herself as straight. Navratilova has since identified herself as a lesbian.

According to the New York Times’ Jane E. Brody, in September 1982, an acute attack of toxoplasmosis “contributed to Martina Navratilova’s defeat during the United States Open tennis tournament”, in which No. 1 seed Navratilova unexpectedly lost to No. 7 seed Pam Shriver in the quarterfinal round. (Shriver—Navratilova’s doubles partner in the same tournament—subsequently lost to No. 5 seed Hana Mandlíková in the semifinal. Mandlíková was then defeated in the final by Navratilova’s longtime rival, No. 2 seed Chris Evert.) By late October, Navratilova had “apparently recovered”.

In 1983, Martina Navratilova and Vijay Amritraj appeared in the Hart to Hart episode “Love Game” as themselves, as the guests of honor at a charity tennis event. Her role was the more significant; she partnered with the lead male character Jonathan Hart (Robert Wagner) in a mixed doubles match. In 1996, Navratilova was featured with American football player Art Monk in an endorsement for PowerBook in an ad series “What’s on Your PowerBook?” In 2000 Martina appeared as herself on Will & Grace “Lows in the Mid-Eighties” as one of Karen Walker’s (Megan Mullally) paramours in a flashback sequence. In November 2008, Martina Navratilova appeared on the UK’s ITV series Series 8 of I’m a Celebrity … Get Me Out of Here!; she finished runner-up to Joe Swash. In February 2012 Navratilova was announced as a cast member on the 14th season of ABC’s Dancing with the Stars. She was partnered with Tony Dovolani, but they were the first pair eliminated. Navratilova guest-starred as a dissatisfied Yelp reviewer in episode three of the third season of absurdist comedy Portlandia. Navratilova currently has a recurring role portraying Brigitte, a horse trainer who is also the lover of Georgina (Gwyneth Paltrow), the mother of the titular character Payton Hobart Ben Platt), on the Ryan Murphy produced Netflix series, The Politician.

A left-hander, Navratilova completed a calendar grand slam in women’s doubles in 1984, partnering right-handed Pam Shriver, a tall and talented player whose most noted stroke was a slice forehand, a shot virtually unheard of in the game today. This was part of a record 109-match winning streak that the pair achieved between 1983 and 1985. (Navratilova was ranked the world No. 1 doubles player for a period of over three years in the 1980s.) From 1985 through 1987, Navratilova reached the women’s singles final at all 11 major tournaments held during those three years, winning six of them. From 1982 through 1990, she reached the Wimbledon final nine consecutive times. She reached the US Open final five consecutive times from 1983 through 1987 and appeared in the French Open final five out of six years from 1982 through 1987.

From 1984 to 1991, Navratilova had a long-term relationship with Judy Nelson, whom she met at a tournament in Fort Worth in 1982. Their split in 1991 resulted in a televised palimony lawsuit which was settled out of court.

In 1985, Navratilova played in what many consider to be perhaps the best woman’s match of all time, the French Open final against Chris Evert. Navratilova battled back from 3–6, 2–4 down to 5-5 all in the third set, before Evert hit a winning backhand passing shot on match point to defeat Navratilova 6–3, 6–7(4), 7–5. This was a major turnaround for Evert, who was so outmatched the year earlier in the final that Bud Collins remarked as a TV commentator that the sport needed to create a higher league for Navratilova to compete in. In outdoor matches against Evert, Navratilova led 10–5 on grass and 9–7 on hardcourts, while Evert was up 11–3 on clay. On indoor courts, however, Navratilova had a decisive 21–14 lead. At the end of what is widely regarded as the greatest rivalry in women’s tennis, Navratilova led Evert 43–37 in total matches, 14–8 in Grand Slams and 10–4 in Grand Slam finals.

In 1985, Navratilova released an autobiography, co-written with The New York Times sports columnist George Vecsey, titled Martina in the U.S. and Being Myself in the rest of the world. She had earlier co-written a tennis instruction book with Mary Carillo in 1982, entitled Tennis My Way. She later wrote three mystery novels with Liz Nickles: The Total Zone (1994), Breaking Point (1996), and Killer Instinct (1997). Navratilova’s most recent literary effort was a health and fitness book entitled Shape Your Self, which came out in 2006. An ESPN Documentary was produced about her rivalry with Chris Evert titled, Unmatched. Her rivalry and friendship with Evert is also detailed in the book, The Rivals by Johnette Howard and the children’s book, Martina and Chrissie by Phil Bildner.

Navratilova began to wear glasses in 1985 and recalled that her vision had begun to deteriorate in 1984. She continued to wear glasses for tennis for many years. Few tennis players wear sunglasses regularly for tennis and Navratilova is one of them. Although she achieved so much prior to using glasses, her glasses have become iconic. Some sports writers have said that they made her, as with other top athletes who had imperfect health, seem more vulnerable and human.

In 1986 at the U.S. Open, Navratilova prevailed over sixteen-year-old German Steffi Graf in a close semi-final winning 6–1, 6-7 (7-3), 7-6 (10-8), before handily winning the final over Helena Sukova 6–3, 6–2. Navratilova, with partner Pam Shriver, also won the women’s doubles title. Navratilova also defeated Graf in straight sets at the WTA Tour Championship and with an 89–3 record, earned the number-one ranking for the fifth consecutive year.

Graf dominated the first half of the 1987 season including defeating Navratilova in straight sets in the semi-finals of the Miami Open and in the final of the French Open, 6–4, 4–6, 8–6. However, Navratilova defeated Graf in straight sets in the finals of both Wimbledon and the US Open (and at the US Open became only the third player in the Open Era, joining tennis legends Margaret Court and Billie Jean King, to win the women’s singles, women’s doubles, and mixed doubles at the same event—the rare “Triple Crown”). Navratilova reached all four Grand Slam finals in 1987, winning two of them (she lost the Australian Open to Hana Mandlikova). Graf’s two losses to Navratilova were her only losses of the year and with 11 tournament wins over the year versus 4 for Navratilova she was able to obtain year-end world No. 1 ranking ahead of Navratilova at No. 2. Graf eventually broke Navratilova’s records of 156 consecutive weeks and 331 total weeks as the world No. 1 singles player but fell 60 short of Navratilova’s record of 167 singles titles. Including doubles, Navratilova won almost three times as many titles as Graf with a record doubles/mixed/singles combined total of 344 titles to Graf’s 118.

In 1988, Graf won all four major singles titles, beating the 31-year-old Navratilova 5–7, 6–2, 6–1 in the Wimbledon final, their only match of the year, recovering from a set and a break down. Navratilova did not reach the finals of any of the other Grand Slam events but did win nine tournaments enabling her to claim the No. 2 ranking behind Graf.

In 1989, Graf and Navratilova met in the finals of both Wimbledon and the US Open, with Graf winning both encounters 6–1 in the third set. Graf also defeated Navratilova in the finals of the WTA Tour Championships their third and final match of the year. Navratilova, who skipped the French Open that year, did win eight titles and was able to capture the No. 2 ranking behind Graf for the third straight year. Despite the 13 year age difference between the two players, and Graf’s comparative lack of investment in doubles and mixed doubles, Navratilova won 9 of the 18 career singles matches with Graf and 5 of the 9 major singles matches with her. At age 34, Navratilova defeated Graf the last time they played in a major in the semifinals of the 1991 US Open 7–6(2), 6–7(6), 6–4, to end their Grand Slam rivalry 5-4 up, although it is noteworthy that all 4 of Graf’s Grand Slam victories over Navratilova came in the finals of a Slam. This is reflected in the Grand Slams Finals chart below.

Navratilova’s final Grand Slam singles triumph was in 1990. In the final at Wimbledon, the 33-year-old Navratilova swept Zina Garrison 6–4, 6–1 to claim an all-time record ninth Wimbledon singles crown. She won four other tournaments that year, although she did not participate in the Australian or French Opens, and finished the year ranked No. 3 in the world, narrowing edge out by sixteen-year-old Monika Seles for the No. 2 spot. Though that was her last major singles title, Navratilova reached two additional major singles finals during the remainder of career: in 1991, she lost in the US Open final to the new world No. 1, Monica Seles; and, in 1994, at age 37, Navratilova reached the Wimbledon final, where she lost in three sets to Conchita Martínez. In November that year, after losing to Gabriela Sabatini in the first round of the WTA Tour Championships, she retired from full-time competition on the singles tour. She was inducted into the International Tennis Hall of Fame in 2000.

In September 1992, the 35-year-old Navratilova played 40-year-old Jimmy Connors in the third Battle of the Sexes tennis match at Caesars Palace in Paradise, Nevada. Connors was allowed only one serve per point and Navratilova was allowed to hit into half the doubles court. Connors won 7–5, 6–2. She played for the Boston Lobsters in the World TeamTennis pro league through the 2009 season.

In 1993, Navratilova spoke before the March on Washington for Lesbian, Gay and Bi Equal Rights and Liberation. Navratilova serves as the Health and Fitness Ambassador for AARP in an alliance created to help AARP’s millions of members lead active, healthy lives.

In 2000, Navratilova returned to the tour to mostly play doubles events, while rarely also playing singles. In her first singles performance in eight years, at Eastbourne in 2002, she beat world No. 22, Tatiana Panova, before losing in the next round to Daniela Hantuchová in three sets. In 2003, she won the mixed doubles titles at both the Australian Open and Wimbledon, partnering Leander Paes. This made her the oldest ever major champion (aged 46 years, 8 months). The Australian Open victory made her the third player in history to complete a “boxed set” of major titles by winning the singles, women’s doubles, and mixed doubles at all four majors. The Wimbledon win allowed her to equal Billie Jean King’s record of 20 Wimbledon titles (in singles, women’s doubles, and mixed doubles combined) and extended her overall number of major titles to 58 (second only to Margaret Court, who won 62). Navratilova made a return to singles at the 2004 French Open after an absence of 10 years, but she was defeated by Gisela Dulko in the first round. Shortly afterwards, and despite being criticized for receiving a wildcard, Navratilova won a singles match over Catalina Castaño 6–0 6–1 at the first round of Wimbledon in 2004, aged 47 years and eight months, to make her the oldest player to win a professional singles match in the open era. Navratilova then lost her second round match with the same player who had beaten her at the French Open the previous month, Gisela Dulko, in three sets.

In 2000, she was the recipient of National Equality Award from the Human Rights Campaign, the nation’s largest gay and lesbian activist/lobbying group.

In 2000, she became a member of the Laureus Sports Foundation’s Academy.

Navratilova was a guest on CNN’s Connie Chung Tonight show on July 17, 2002. During the show, Chung quoted a German newspaper which quoted Navratilova as saying:

Navratilova is considered one of the best female tennis players of all time and in 2005, Tennis magazine selected her as the greatest female tennis player for the years 1965 through 2005, directly over Steffi Graf. Billie Jean King, a former World No. 1 player, said in 2006 that Navratilova is “the greatest singles, doubles and mixed doubles player who’s ever lived.” In 2008, tennis historian and journalist Bud Collins called Navratilova “arguably, the greatest player of all time.”

Navratilova won 167 top-level singles titles (more than any other player in the open era) and 177 doubles titles. Her last title in women’s doubles came on August 21, 2006, at the Tier I Rogers Cup in Montreal, Quebec, Canada, where she partnered Nadia Petrova. Navratilova won 18 major singles titles: nine at Wimbledon, four at the US Open, three at the Australian Open, and two at the French Open. Her overall record in 67 major singles events was 306–49 (120–14 at Wimbledon, 89–17 at the US Open, 51–11 at the French Open, and 46–7 at the Australian Open). Some observers argue that the very few singles matches she played in her forties should be counted separately in her career statistics. She is the only player to have won at least one tour event for 21 consecutive years and won the singles and doubles at the same event a record 84 times. She was ranked in the world top 3 in singles for 15 years between 1977 and 1993. Her career singles match win total of 1,442 is the most during the open era.

In 2006, Martina Navratilova was named by Equality Forum as one of their 31 Icons of the LGBT History Month.

Navratilova was quoted in 2007 as being ashamed of the US under President George W. Bush because unlike the communist regime in Czechoslovakia, Bush was democratically elected.

In 2009, Navratilova was awarded the International Tennis Federation’s (ITF) highest accolade, the Philippe Chatrier Award, for her contributions to tennis both on and off the court.

On April 7, 2010, Navratilova announced that she was being treated for breast cancer. A routine mammogram in January 2010 revealed that she had a ductal carcinoma in situ in her left breast, which she was informed of on February 24, and in March she had the tumour surgically removed; she received radiation therapy in May.

In December 2010, Navratilova was hospitalized after developing high altitude pulmonary edema while attempting a climb of Mount Kilimanjaro in Tanzania.

In June 2011, she was named one of the “30 Legends of Women’s Tennis: Past, Present and Future” by Time.

In March 2012, The Tennis Channel named Navratilova as the second greatest female tennis player of all times, behind Steffi Graf, in their list of 100 greatest tennis players of all times.

On August 2, 2013, Navratilova was among the first class of inductees into the National Gay and Lesbian Sports Hall of Fame.

In December 2014, it was announced that Navratilova had joined Agnieszka Radwańska’s coaching staff. However, in April 2015, after Radwańska struggled in the first half of the season, the pair decided to part ways.

On September 6, 2014, Navratilova proposed to her long-time girlfriend Julia Lemigova at the US Open. They married in New York on December 15, 2014.

On May 12, 2016, Navratilova was made an honorary fellow of Lucy Cavendish College of the University of Cambridge.

Navratilova is critical of allowing trans women to compete in women’s sports. She rejects accusations of transphobia, and says she deplores “a growing tendency among transgender activists to denounce anyone who argues against them and to label them all as ‘transphobes.'” Following an article on the subject that Navratilova wrote for The Times in February 2019, Athlete Ally, an LGBTQ athlete advocacy group, removed Navratilova from their advisory board, stating her comments “are transphobic [and] based on a false understanding of science and data”.

In March 2019, Navratilova apologized for using the term “cheating” when discussing whether transgender athletes should be allowed to compete in women’s sport. She also called for “a debate, a conversation that includes everyone and is based, as I have said, not on feeling or emotion but science.”

In June 2019, the BBC broadcast “The Trans Women Athlete Dispute with Martina Navratilova”, where she interviewed people including trans women athletes and sports researchers, presenting evidence on both sides of the debate of whether trans women have any advantage in elite sports. Her closing remarks were “The way I started this journey, I just wanted to see if there are any big surprises, any misconceptions that I had. And what I think I have come to realise, the biggest thing for me, is just that the level of difficulty that trans people go through cannot be underestimated. The fight for equality and recognition is just huge. That being said, still, for me, the most important thing in sports… and you have to remember, trans rights and elite sports are two different things, although of course they are connected. What’s the right way to set rules so that everybody feels like they have a fighting chance? It feels to me that it is impossible to come to any real conclusions or write any meaningful rules until more research is done.

In August 2020, Navratilova along with 300+ women signed a letter to the National Collegiate Athletic Association in support of an Idaho law that bans transgender female student athletes from competing in women’s and girls sports.