Billie Jean King is one of the world’s most celebrated tennis players, but just as impressive is her dedication to fighting for equality and breaking down barriers both on and off the court. King started off in softball until her parents suggested she try a different sport. She switched to tennis at age 11, and after her first lessons, she told her mother she would be No. 1 in the world. And she was right.

King held the No.1 title five times between 1966 and 1972 and for more than 20 years, she dominated the tennis world. She won 39 Grand Slam singles, doubles, and mixed doubles tennis titles, including a record 20 titles at Wimbledon.

But for all her tennis accomplishments, she is probably best known for her 1973 match against former men's champion Bobby Riggs in the "Battle of the Sexes." She said afterwards, "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." But even under that enormous pressure, she emerged victorious.

King's accomplishments have gone beyond her skill as a player as well, as she notably lobbied for equal prize money and gender equity. In 1973, she spearheaded the formation of the Women's Tennis Association (WTA). She threatened to boycott tournaments if the pay inequality was not addressed, and the U.S. Open became the first major organization to grant her request.

“In the seventies we had to make it acceptable for people to accept girls and women as athletes. We had to make it okay for them to be active,” she once said.

Even after retiring, she continued her work as an influential social activist and wrote numerous books. She was also the first prominent woman athlete to come out as gay and became a torchbearer for the LGBTQ+ community. In 2009, she was awarded the Presidential Medal of Freedom by Barack Obama and in 2014, she founded the Billie Jean King Leadership Initiative, a non-profit dedicated to promoting equality in the workplace.

King has been a life-long equality campaigner as well as a trailblazer in sport. Through her actions, she has given everyone a chance to compete on the court and in life, regardless of gender or sexual orientation.