Billie Jean King was a tennis player.
Billie Jean King ( née Moffitt ; born November 22 , 1943 ) 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 . In 1973 , at age 29 , she won the Battle of the Sexes tennis match against the 55-year-old Bobby Riggs , and was the founder of the Women 's Tennis Association , World TeamTennis ( with former husband Larry King ) , and the Women 's Sports Foundation . The Grand Slam tournaments , also called majors , are the four most-important annual tennis events .