Billie Jean King

Billie Jean King's 1973 victory over Bobby Riggs in the Battle of the Sexes was watched by 90 million people worldwide, making it the most-watched tennis match in history and a pivotal moment for women's rights. She won 39 Grand Slam titles across singles, doubles, and mixed doubles, a total that is 10 more than #7 Nadia Comaneci's Olympic and World Championship medals combined. King founded the Women's Tennis Association in 1973, securing equal prize money for female players, a move that increased prize purses by 50% within three years. Her impact off the court outpaces #5 Mia Hamm's advocacy by creating the structural framework for professional women's sports.