After a successful amateur career, which culminated in his Olympic gold medal win, Spinks went undefeated in his first 31 professional fights, beating Dwight Muhammad Qawi, Eddie Mustafa Muhammad, Marvin Johnson and Eddie Davis en route to becoming the undisputed light heavyweight champion. After defending the title against 10 different fighters, Spinks moved up to heavyweight, and as an underdog defeated long-reigning IBF heavyweight champion Larry Holmes (whose own 48–0 record up to that point was one victory short of tying Rocky Marciano's 49–0 unblemished scorecard); in doing so, Spinks became the first reigning light heavyweight world champion to win the heavyweight title. In his final fight, Spinks was knocked out by Mike Tyson in 91 seconds, the only defeat of his professional career.