Spinks defeated Muhammad Ali in 1978 before losing a rematch, died on Friday, according to his publicists. He was 67.
Spinks died with his wife, Brenda Spinks, at his side, after a five-year battle with cancer. He had been admitted to a Las Vegas hospital in December, according to a statement from The Firm PR to Las Vegas television station KVVU on Saturday.
With a trademark toothy grin, Spinks fought his way to Olympic gold in 1976 as a US light heavyweight in Montreal and turned professional six months later at age 23.
After only eight professional fights, seven wins and a draw, Spinks was sent into the ring against iconic Muhammad Ali on February 15, 1978 at the Las Vegas Hilton.
Spinks finished his career with a record of 26-17, with three draws and 14 knockouts [File: Robert Galbraith/Reuters]
Spinks won a 15-round split decision over a 36-year-old Ali, who lost World crowns in the ring for the only time in his career, falling to 55-3 as Spinks claimed the heavyweight title in the shortest time of any fighter in history, only 13 months after his pro debut.
Seven months later, in a rematch before 70,000 at the Superdome in New Orleans, a fit and formidable Muhammad Ali won a unanimous 15-round decision in what would be the final victory of his legendary career, making him the first three-time champion in heavyweight history.
Spinks had been stripped of the World Boxing Council crown for taking the rematch with Ali rather than face mandatory challenger Ken Norton, so the second fight was only for the World Boxing Association title.
WBA Champion Leon Spinks lands a right to Muhammad Ali against the ropes during their heavyweight title bout at the Superdome in New Orleans, September 15, 1978. Spinks lost his next fight as well but earned another shot at the crown in 1981 against Larry Holmes, only to be stopped in the third round..