A Champion On and Off the Court: Billie Jean King’s Activism

Billie Jean King is far more than a tennis legend with 39 Grand Slam titles. She is one of the most consequential activists in the history of American sports, a figure whose work off the court has arguably had a more lasting impact than her achievements on it. Her relentless fight for gender equality, equal pay, and social justice did not end with her playing career—it fundamentally reshaped the athletic landscape for generations of women. For modern female athletes, King did not merely open doors; she tore down entire walls. Her activism, beginning in the late 1960s and continuing through today, provides both a blueprint and a moral compass for stars like Serena Williams, Megan Rapinoe, Naomi Osaka, and countless others who now use their platforms to demand fairness, representation, and systemic change. Understanding King’s influence is essential to understanding the modern era of women’s sports, an era defined not just by athletic excellence but by advocacy.

The Roots of a Revolutionary: Early Activism and Breakthrough Moments

Billie Jean King’s activism was born from direct, personal experience. As a young amateur tennis player in the 1960s, she quickly recognized that the sport was deeply unequal. Male players earned significantly more prize money, received better media coverage, and enjoyed far greater institutional support. King understood that talent alone was not enough; the system itself was rigged against women. Her first major act of defiance came in 1968, when she skipped the U.S. Amateur Championships to play in a professional tournament, openly criticizing the United States Lawn Tennis Association (USLTA) for its lack of support for female players. This was a risky move for a 24-year-old athlete, but it established her pattern of prioritizing principle over personal convenience.

Forming the Original Nine

King’s single most important early act of activism was her role in founding the Virginia Slims Circuit, the precursor to the Women’s Tennis Association (WTA). In 1970, frustrated that women’s tournaments offered as little as one-eighth the prize money of men’s events, King and eight other female players—known as the "Original Nine"—signed symbolic one-dollar contracts with publisher Gladys Heldman to create their own tour. This was a revolutionary act of self-determination. The players risked being banned by the USLTA and losing their eligibility for Grand Slam events. King did not just join this effort; she was its driving force, using her status as a top-ranked player to lend legitimacy and leverage to the fledgling tour. The formation of the Virginia Slims Circuit was the birth of professional women’s tennis as a viable, independent entity, and it laid the groundwork for every financial opportunity modern female tennis players enjoy.

The Fight for Equal Pay at the US Open

King’s activism was never just about creating separate opportunities for women; it was about achieving equal standing within the existing structures. In 1972, after winning her third US Open title, King publicly threatened to boycott the tournament the following year unless the prize money for the women's champion was made equal to that of the men’s champion. This was a direct challenge to the United States Tennis Association (USTA). Her threat was credible, and the USTA capitulated. In 1973, the US Open became the first major sporting event in the world to offer equal prize money to men and women. This victory was a landmark not just for tennis but for all of women’s sports. It established a powerful precedent: the idea that women’s athletic achievements are worth exactly the same as men’s. The fight for equal pay has continued in other sports and tournaments—Wimbledon did not introduce equal prize money until 2007—but King’s victory at the US Open provided the foundational argument used by every athlete who has since demanded pay equity.

The Battle of the Sexes: A Cultural Earthquake

No single event in sports history has done more to challenge gender stereotypes than the 1973 "Battle of the Sexes" match between Billie Jean King and Bobby Riggs. Riggs, a 55-year-old former Wimbledon champion and self-proclaimed male chauvinist, had been loudly proclaiming that even a middle-aged man could beat the best female player in the world. After defeating Margaret Court in the "Mother’s Day Massacre" in May 1973, Riggs turned his attention to King. She initially declined, but after Riggs’ victory over Court, King realized she had to accept. She understood that the match was far more than an exhibition; it was a proxy battle for the legitimacy of women’s athletics.

More Than a Tennis Match

The match, held on September 20, 1973, at the Houston Astrodome, was broadcast live on ABC and was watched by an estimated 90 million people worldwide—one of the largest television audiences in history. The spectacle was immense: Riggs arrived on a rickshaw pulled by models dressed as gladiators, while King was carried in on a litter carried by shirtless men. The match itself was a decisive victory for King, who defeated Riggs 6-4, 6-3, 6-3. But the outcome had implications far beyond the score. King’s victory was a public, visceral refutation of the idea that women’s sports were inherently inferior. It provided a cultural moment that shifted public consciousness. As King herself famously said, "I thought it would set us back 50 years if I didn’t win that match. It would ruin the women’s tour and affect all women’s self-esteem." The match remains one of the most significant cultural events of the 20th century, a moment when a female athlete defeated not just an opponent but an entire ideology of male superiority.

Lasting Cultural Impact

The Battle of the Sexes had a direct and measurable effect on the participation of women in sports. In the decade following the match, female participation in high school sports in the United States increased by over 600%, driven in part by the passage of Title IX in 1972 but also by the cultural permission King’s victory provided. The match also helped legitimize the idea that female athletes could be mainstream, marketable stars. Companies began to see the commercial value of sponsoring women’s sports, and media outlets began to take female athletes more seriously. For modern female athletes, the Battle of the Sexes is the foundational myth of their professional existence—it is the moment that proved they could compete on the biggest stage and win the attention of the world.

Institutional Change: Founding the WTA and Advocacy for Title IX

While the Battle of the Sexes was a spectacular cultural event, King’s most enduring contributions to women’s sports have been institutional. In 1973, immediately after her victory over Riggs, King founded the Women’s Tennis Association (WTA), the first and still the most successful union for female athletes in any sport. The WTA was designed to give women players a unified voice in negotiations with tournaments, sponsors, and governing bodies. King served as the WTA’s first president, and her leadership was instrumental in securing better prize money, more tournament opportunities, and improved working conditions for players. The WTA model has been studied and emulated by other women’s sports organizations, including the NWSL Players Association and the Women’s National Basketball Players Association (WNBPA).

Title IX and Broader Social Change

King was also an early and vocal supporter of Title IX, the 1972 federal law that prohibits sex-based discrimination in any educational program or activity receiving federal funding. While Title IX is most famous for its impact on school sports, King understood its potential to transform the entire ecosystem of women’s athletics. She testified before Congress, spoke at universities, and used her media platform to advocate for the law’s full implementation. King’s advocacy helped ensure that Title IX was enforced in athletics, requiring schools and universities to provide equal opportunities for female athletes. This law has been responsible for the explosion of women’s collegiate sports in the United States, creating the pipeline of talent that now feeds professional leagues and national teams. King’s connection to Title IX remains strong; the Billie Jean King Leadership Initiative continues to advocate for the law’s enforcement and expansion.

The Influence on Modern Female Athletes: Carrying the Torch

The direct line from Billie Jean King’s activism to the current generation of female athletes is visible in almost every major advocacy moment in modern sports. King did not just create opportunities; she created a template for how elite female athletes can use their platforms. The modern athlete-activist does not exist in isolation—they are standing on the shoulders of King and the Original Nine.

Serena Williams: Equal Pay and Maternal Rights

Serena Williams has frequently cited Billie Jean King as a direct inspiration for her own advocacy. Williams has been one of the most vocal proponents of equal pay in tennis, and she has explicitly acknowledged that King’s victory at the 1973 US Open paved the way for her own fight. In 2016, ahead of the Indian Wells tournament, Williams wrote an essay for The Verge titled "The Meaning of Serena Williams," in which she credited King and the Original Nine for their courage. Williams has also taken up causes that extend beyond King’s original platform, including advocating for maternal health and pay equity for women of color. King has publicly supported Williams, calling her a "true champion for equality." Williams’ willingness to use her platform to speak out on social issues—from police brutality to maternity leave policies—is a direct extension of the activist template King established in the 1970s. The WTA’s continued commitment to equal rights is a living legacy of King’s foundational work.

Megan Rapinoe: Intersectional Activism and Collective Bargaining

Megan Rapinoe, the U.S. Women’s National Team (USWNT) star and two-time World Cup champion, represents perhaps the most direct continuation of King’s activist legacy in team sports. Rapinoe has been a leading voice in the USWNT’s fight for equal pay, a five-year legal battle that culminated in a historic $24 million settlement with U.S. Soccer in 2022. Rapinoe has repeatedly cited King as a model for her own activism. Like King, Rapinoe understands that individual talent is not enough—systemic change requires collective action and a willingness to risk personal popularity. Rapinoe has also expanded the scope of athlete activism to include LGBTQ+ rights and racial justice, causes that resonate with King’s lifelong commitment to social justice across multiple fronts. King and Rapinoe have developed a close personal and professional relationship; King has served as a mentor to Rapinoe and has publicly praised her for extending the fight for equality into new arenas.

Naomi Osaka and the New Model of Athlete Activism

Naomi Osaka, a four-time Grand Slam champion from Japan, represents a newer, more personalized model of athlete activism that still draws on King’s example. Osaka has used her platform to speak out on racial justice, particularly in the wake of the murder of George Floyd, and she has been open about her struggles with mental health, a topic King also addressed during her career. In 2021, Osaka withdrew from the French Open after being fined for refusing to participate in mandatory press conferences, citing her need to protect her mental well-being. While the situation was controversial, Osaka’s willingness to prioritize her own health over institutional expectations echoed King’s willingness to defy the tennis establishment for the sake of principle. King publicly supported Osaka, stating that her decision was a form of advocacy that would help change the culture of professional sports. Osaka has also used her financial resources to support social causes, donating prize money to earthquake relief in Haiti and launching a line of masks featuring the names of Black victims of police violence. This integration of personal brand, athletic success, and social advocacy is a direct evolution of the model King pioneered.

Coco Gauff: The Next Generation

At just 19 years old, Coco Gauff is already demonstrating the influence of King’s legacy. Gauff has spoken at Black Lives Matter protests, used her media interviews to call for climate action, and publicly supported her peers in the fight for equal conditions in tennis. In 2023, Gauff was awarded a leadership prize by the WTA, and she has cited King as a role model. Gauff represents the generational transmission of King’s values—an athlete who understands that her platform comes with a responsibility to advocate for a better world. King has watched this new generation with pride, noting that the activism of young players like Gauff and Osaka is evidence that the movement she started is alive and growing.

Legacy and Ongoing Challenges: The Work Continues

Despite the monumental progress enabled by King’s activism, significant challenges remain. Equal pay in many sports is still a distant goal, representation in leadership positions remains skewed, and media coverage of women’s sports still lags far behind men’s. These ongoing issues underscore the necessity of King’s central message: the fight for equality is never finished.

The Persistent Pay Gap

While tennis has achieved equal prize money at the Grand Slams, most other sports have not. In basketball, the WNBA salary cap is a fraction of the NBA’s, and while the WNBA has made strides in recent years, the disparity remains enormous. In soccer, despite the USWNT’s historic settlement, the fight for global pay equity continues. The FIFA Women’s World Cup prize money, while increased for 2023, is still only 25% of the men’s prize pool. King has continued to speak out on this issue, arguing that the value of women’s sports must be recognized not just by the public but by the institutions that control the funding.

Media Coverage and Sponsorship

Women’s sports receive only about 5% of total sports media coverage in the United States, a figure that has barely budged in decades despite dramatic increases in participation and viewership. This lack of coverage creates a self-perpetuating cycle: less visibility means fewer sponsorship dollars, which means lower salaries and less investment. Athletes like Rapinoe and Williams have worked to break this cycle by being vocal about their own value and by creating their own media content. King’s early work with Virginia Slims—essentially creating a new media product for women’s tennis—provides a template for how athletes can take control of their own narratives. The Women's Sports Foundation, which King co-founded in 1974, continues to advocate for greater media coverage and investment in women’s sports.

Leadership and Representation

There is also a significant gap in leadership. As of 2024, women hold a minority of head coaching positions in NCAA women’s sports, and only a handful of professional women’s teams have female majority owners or general managers. In the boardrooms of sports governing bodies, women remain underrepresented, even in organizations that govern women’s sports. King has consistently argued that the fight for equality must include a fight for decision-making power. Without women in positions of authority, she argues, the priorities of women’s sports will always be secondary. The WTA’s governance structure, which includes player representation at the highest levels, was designed by King to address this problem directly.

The Enduring Lessons of Billie Jean King’s Activism

Billie Jean King’s activism teaches several core lessons that remain profoundly relevant for modern female athletes. The first is that personal success is not enough. King was already the world’s best tennis player when she began her fight for equal pay and opportunities. She risked her career—and her reputation—to demand better conditions not just for herself but for all women. Modern athletes have inherited this understanding: that a championship is a platform, not a final destination. The second lesson is that systemic change requires institutional power. King did not just protest inequality; she built a union, created a tour, and founded organizations that could outlast her. The WTA, the Women’s Sports Foundation, and the Billie Jean King Leadership Initiative are not just monuments to her career—they are operational tools for ongoing advocacy. The third lesson is that allyship and coalition-building matter. King worked tirelessly with men, including promoting co-ed events and mentoring male athletes on gender issues. She understood that achieving equality requires changing the minds of those in power, not just empowering the marginalized.

The final, most urgent lesson from King’s life is that the fight for equality is intergenerational. King has never presented herself as a solitary figure who single-handedly solved the problem of gender inequality. Instead, she has consistently emphasized that each generation must take up the cause. She has handed the baton to Serena, to Megan, to Naomi, and to Coco, trusting them to run with it in their own ways. For modern female athletes, Billie Jean King is not a historical figure to be admired from a distance. She is a living mentor who remains actively engaged in the movement she helped start. Her voice still matters, her presence still commands attention, and her example still inspires. The work of equality is unfinished, but because of Billie Jean King, the next generation of female athletes will never have to start from zero. They will start from the foundation she built, and with that advantage, they will go further than even she could have imagined.