Muhammad Ali, formerly Cassius Clay, US heavyweight boxer, born at Louisville, Kentucky. He won the light-heavyweight gold medal at the Rome Olympics, 1960, and turned professional later that year, being sponsored by 11 millionaires. He took the world heavyweight title from Sonny liston on 25 February 1964 in his 20th paid contest. He took the name Muhammad Ali after this date, and also became a Muslim.
He made nine successful defences of his title, but then was deprived of it for refusing to join the US army. He remained inactive for three years before suffering the first defeat of his career (1971) when trying to regain his title from Joe frazier. However, he regained the heavyweight crown for the second time (the second man in boxing history to do so) from George foreman in eight rounds at Kinshasa, Zaire.
Ali was an extremely able boxer, using the ring and ropes in overtly defensive fashion, wearing down his opponents with well-timed punching ability.