Discover the inspiring life of Billie Jean King, the tennis star who has dedicated her life to breaking barriers both on and off the tennis court. Billie Jean began playing tennis at the age of 11. After one of her first tennis lessons, she told her mother, ‘I'm going to be No. 1 in the world’, a title she would come to hold five times between 1966 and 1972. Twenty years later, she is still considered one of the most successful women in sport history.