Leon Spinks (born July 11, 1953) is an American former professional boxer who competed from 1977 to 1995. In only his eighth professional fight, he won the undisputedheavyweight championship in 1978 after defeating Muhammad Ali in a split decision, in what was considered one of the biggest upsets in boxing history. Spinks was later stripped of the WBC title for facing Ali in an unapproved rematch seven months later, which he lost by unanimous decision.