Billie Jean King is an American former World No. 1 professional tennis player. King won 39 Grand Slam titles: 12 in singles, 16 in women's doubles, and 11 in mixed doubles. She won the singles title at the inaugural WTA Tour Championships. She often represented the United States in the Federation Cup and the Wightman Cup. She was a member of the victorious United States team in seven Federation Cups and nine Wightman Cups. For three years, she was the United States' captain in the Federation Cup.
King is an advocate for gender equality and has long been a pioneer for equality and social justice. In 1973, at age 29, she won the "Battle of the Sexes" tennis match against the 55-year-old Bobby Riggs. She was also the founder of the Women's Tennis Association and the Women's Sports Foundation. She was also instrumental in persuading cigarette brand Virginia Slims to sponsor women's tennis in the 1970s and went on to serve on the board of their parent company Philip Morris in the 2000s.
Regarded by many in the sport as one of the greatest women's tennis players of all time, King was inducted into the International Tennis Hall of Fame in 1987.