The tennis champion’s activism won equal pay for women at the 1973 U.S. Open. Now 79, she is still leading the fight for equity — in sports and beyond.The more Billie Jean King talked about the past, the more animated she became about the future.King, the 79-year-old grand champion of tennis and gender equity, said she wanted to see more investment in women’s sports. More teams. More leagues. More women owners. More racial diversity, more data, more access and more opportunities.She charged crosscourt from one topic to the next, not content to celebrate the history she had made; she was too busy creating the template for tomorrow.“Equal investment is the most important thing,” she said during a telephone interview from London, while attending this year’s Wimbledon. “If I talk to a C.E.O., I ask him, or her, or whoever, ‘Do you spend as much on women’s sports as men’s sports?’ That’s the magic question.”It always has been.This summer marks 50 years since the United States Open awarded equal prize money for men and women, becoming the first of the four Grand Slam tennis tournaments to offer it. King, who won 39 major titles, made that milestone possible with her relentless activism and by securing corporate sponsors behind the scenes.King celebrates after defeating Margaret Court in their women’s singles second-round match at Wimbledon in 1962. King went on to capture 20 Wimbledon titles.Central Press/Hulton Archive, via Getty ImagesOn the eve of the 2023 FIFA Women’s World Cup — set to showcase the rise of women’s soccer and the movement for equal pay, led by the U.S. Women’s National Team — King’s influence still ripples through the sports ecosystem.“She is working as hard today as she was 50 years ago,” said Stacey Allaster, the United States Tennis Association’s chief executive of professional tennis, and the first female director of the U.S. Open, said. “And she’s so focused, I would say possessed. She’s continuing to live by what she believes: that sport is for social change, and it’s not what you get, but what you give.”King and her wife, Ilana Kloss, who is also her longtime business partner, have invested in six sports. In June, it was announced that Billie Jean King Enterprises would help run a new six-team women’s ice hockey league starting in January along with the Los Angeles Dodgers’ majority owner, Mark Walter, and his wife, Kimbra Walter.“We believe this is transformational, and it’s a sport that hasn’t had the platform that we believe it needs,” said Kloss, 67, a former doubles champion from South Africa and the chief executive of BJK Enterprises.Although she admitted that the path to establishing a successful women’s hockey league has been a “long road” (one that’s littered with past failures), she applauded the Walters’ commitment to women’s sports. “That belief sends an incredible message to the rest of the investment community,” Kloss said.Flashback to 1970 when King and eight other players, outraged the men were earning more than eight times the prize money that the women were at one tournament, signed $1 contracts to form a offshoot professional women’s tennis tour. The women, known as the “original nine,” risked being banned by tennis officials, but the gambit worked. In 1973 at Wimbledon, King led players in a vote that created what is now called the Women’s Tennis Association.King speaking before the Senate education subcommittee in Washington in 1973. After Title IX was passed, King started the Women’s Sports Foundation to develop more sports opportunities for girls and women.Associated PressIt was a heady time for women’s sports. In 1972, Congress enacted Title IX, which prohibited sex discrimination in schools and thus led to the creation of sports programs that spawned a generation of female athletes. Against that backdrop, King, No. 1 in the world, won the 1972 singles titles at the French Open, Wimbledon and the U.S. Open.In New York, she was incensed to earn $10,000 — $15,000 less than the U.S. Open men’s champion, Ilie Nastase, did. King recalled how she met then with the tournament director Bill Talbert in a referees hut.Turning her chair to face him in the tiny space, she argued that a fan poll showed massive interest in women’s tennis. Then she revealed her ace: She had secured a sponsor — Bristol Myers’s “Ban” deodorant — to make up the difference in total prize money. Equal prize money became official in 1973.A few weeks after the 1973 U.S. Open, King crushed former No. 1 Bobby Riggs in the Battle of the Sexes spectacle that catapulted gender equality onto a world stage.“It’s hard to believe that 50 years have gone by — boink!” King said.This year’s U.S. Open, starting Aug. 28, will mark the equal prize money anniversary in multiple ways, including posters of King, an opening night tribute and an “equity lounge” on the site of the United States Open in Flushing, which in 2006 was renamed the USTA Billie Jean King National Tennis Center.When she’s on the way to her office there, Allaster touches a sign bearing King’s motto: “Pressure is a Privilege.”Allaster, the previous chief of the WTA, said King was an “accessible leader,” not just for her, but for rookies and superstars alike. Allaster called Venus Williams a “modern-day Billie Jean King” for how, during her prime, Williams lobbied Wimbledon officials — and by extension the French Open — to award equal prize money to women.King’s advocacy has always transcended tennis. She started the Women’s Sports Foundation in 1974 to develop sports opportunities for girls and women post-Title IX. After she was publicly outed for being gay in 1981 and lost many of her endorsements, she later became an activist for gay rights.King standing with her wife, Ilana Kloss, also her business partner of more than 40 years. The pair have invested in six sports, including women’s hockey.Chris Tanouye/Freestyle Photography, via Getty ImagesPhaidra Knight, a World Rugby Hall of Fame player and past president of the Women’s Sports Foundation, said King created an inclusive culture at the group. “Through that LGBTQ+ lens and her courage, she has inspired courage in many other lanes, for people to work together,” Knight said in an interview.Beyond King’s encouragement of her as a Black and gay woman, Knight said she valued how King taught her to approach rugby officials to improve business opportunities for the women’s game.Angela Ruggiero, another past president and a former women’s ice hockey Olympian, has also followed King’s lessons. She co-founded the Sports Innovation Lab, a market research company that uses analytics to understand digitally savvy sports fans. Her research shows that fans of every gender are responding to women’s sports. She has frequent brainstorming sessions with King, who never stops asking questions.“We’re going back and forth on how do we bring more capital into women’s sports,” Ruggiero said. “She’ll be at the edge of her seat, fired up. It’s just her nature to be an agent of change.”King said she secretly advised the soccer player Julie Foudy and eight of her teammates in 1995 to hold out for fair contracts and get the younger players behind them. The team won the 1996 Olympics and ignited the frenzy for women’s soccer by winning the 1999 Women’s World Cup before 90,185 fans in the Rose Bowl.Twenty years later, Megan Rapinoe led the U.S. women to another World Cup victory, this time with the fans chanting “Equal Pay.” In 2022, the women’s national team settled its gender discrimination lawsuit against the national federation for $24 million, and a pledge to equalize salaries and prize money.Megan Rapinoe led Team USA to victory at the 2019 World Cup, as fans in the stands shouted “Equal Pay.” Rapinoe recently said that the 2023 World Cup will show that “equality is good for business.”Alex Grimm/Getty ImagesLast month, Rapinoe talked at a news conference about how the 2023 World Cup would be a game-changer for women’s sports, showing that “equality is actually good for business.”King chuckled.“Every generation thinks they are the first to say this — it’s fun to listen to them,” she said. “I’m glad we’re on the same page trying to get things done.”As always, capital is key. She and Kloss — who joined the celebrity ownership group of Angel City Football Club of the National Women’s Soccer League in 2020 — were encouraged by Y. Michele Kang’s recent $35 million purchase of the league’s Washington Spirit.“We need more people to continue to step up,” King said. “If you look at everything now, it’s the billionaires. And then you look at the Middle East, that’s going to be another thing.”In a news conference, King supported the WTA’s exploration of funding from Saudi Arabia, which has already bought in to professional golf with its LIV Golf merger with the PGA Tour. Although she acknowledged the country’s discriminatory policies around women and homosexuality, she told reporters, “I don’t think you really change unless you engage.” She added that this was her opinion. “I’d still probably go and try to talk with them,” she said.Engagement has always been King’s life philosophy, along with knowing your history. She’s not ready to finish writing hers.In November, King will turn 80.“She really has a sense of running out of time,” Kloss said, “and she can’t get enough.” More