Women that changed sport: Billie Jean King keeps serving up change – in tennis and beyond

To watch Billie Jean King walk into an intimate room – for an interview, a speaking engagement, a meet-n-greet – is to witness a legend who needs no introduction doing just that: Introducing herself.

"Hi, I'm Billie Jean," she says, over and over again, as she walks around the room to shake each person's hand and look them in the eye.

It's a singular approach that is a window into the mindset of a tennis champion who has transformed herself not only as a champion for female sport, but also for women's rights and equality across society.

“Billie Jean says often, ‘Interesting people are interested.’ She asks everybody about themselves; she wants to learn about everyone's story,” said actress Emma Stone in 2017 after starring as Billie Jean in the biopic, Battle of the Sexes, which told the true story of King’s famous game-changing 1973 clash with Bobby Riggs.

“She truly loves people. She is a true humanitarian. I think that that spirit was vital to try to even get the edges of [her], [but] I could never quite live up to ‘the’ Billie Jean,” Stone added.

Thee Billie Jean is nearly impossible to live up to – or put into words. Having reached world No.1 in both singles and doubles in women’s tennis by 1967, King set about pushing for equality in women’s tennis, both in terms of equal pay (achieved at the US Open in 1973) and in the formation of the Women’s Tennis Association (WTA) earlier that summer.

She hasn’t stopped in the 50 years since either of those monumental moments, either, becoming a leading voice across a myriad of issues, even after her 80^th birthday celebrated last November.

“Sports are a microcosm of society, but at least we’re going in the right direction,” King told U.S. broadcaster PBS last year. “Women’s tennis has always been a leader when it comes to women’s sports, so we have the opportunity to help make this world a better place.”

• Women's tennis stars still inspired by King today (2023)
• Billie Jean King drops puck for pro women's hockey launch

Venus Williams on Billie Jean King: 'An inspiration'

2023 was a big year for King and women’s tennis: It marked the 50^th anniversary of both the aforementioned pivotal moments at the US Open and WTA, while also marking a half century since that “Battle” against Riggs drew over 30,000 fans at the Astrodome in Houston and was watched by some 90 million people worldwide.

“I had to win” that match, King said on TODAY in 2017 as the movie was released. “But I also had to be connected to the audience... our jobs [as players] is to entertain the audience.”

King has weighed that balance of entertainment with off-court politics throughout, including with being an advisor and advocate in the fight for Title IX in U.S. collegiate sports as well as forming the Women’s Sports Foundation, which still works to move forward the opportunities for women and young girls, both at the professional level and grassroots.

It took a full 34 years for Grand Slam tennis to come full circle: In 2007, with Venus Williams picking up the torch, Wimbledon became the last of the four majors in the sport to provide equal prize money for both the women and the men.

Even as female tennis players crowd highest-paid women's sport lists annually, pay discrepancy still exists, however, between the WTA and ATP, the men’s tour, which are run separately but come together at large dual-gender events.

Williams, who has become an icon in the fight for equality in women’s sports as well, wrote this during last year’s US Open: “The courage, fortitude and commitment that have defined Billie Jean all of her life has been an inspiration to me and to so many others — men and women... It’s one thing to follow a path; it’s quite another thing to blaze that path.”

BJK: 'We need to invest in women's sports'

While her legacy is sealed, King is tireless. She has thrown her name, sporting political capital and expertise across a variety of causes in female sport, including the new women’s professional hockey league, the PWHL.

“I am unbelievably excited to be on hand as the dream for these players become a reality,” King said, dropping the puck for the inaugural game in Toronto earlier this year.

The PWHL has seen huge attendance numbers, including a record 19,285 fans at a game in Toronto 17 February that set an all-time mark for women’s hockey.

The PWHL’s success comes after a record-breaking season for both the WNBA in women’s basketball and the NWSL (women’s football), the latter in which King is a part-owner of a club, Angel City FC in Los Angeles.

“We need everyone to invest in women's sports,” King said when she was added to the ownership group that also includes legendary female athletes (and Olympic gold medallists) Lindsey Vonn and Candace Parker.

It’s a call that many have heard, namely the next generation of women’s superstars, including Parker, Vonn, Venus and beyond.

“Billie Jean is just the epitome of what a strong woman can do in the world when working hard. She’s been just this pillar of equality,” Vonn told CNN Sport in 2023. “She’s such an icon and she has never stopped working towards equality.”