Spinks debuted professionally on January 15, 1977, in
Las Vegas, Nevada, beating Bob Smith by knockout in five rounds. His next fight was in
Liverpool, England, where he beat Peter Freeman by a first-round knockout. Later, he saw an improvement in opposition quality, when he fought Pedro Agosto of
Puerto Rico and knocked him out in round one. He then fought
Scott LeDoux to a draw and defeated Italian champion Alfio Righetti in a decision.
Spinks vs. Ali At the time a lower-ranked contender, he made history on February 15, 1978, by decisively beating
Muhammad Ali on a 15-round split decision, that was in actuality fairly one-sided, in Las Vegas, Nevada. Spinks won the world heavyweight title in his eighth professional fight, the shortest span in history. The aging Ali had expected an easy fight, but he was out-boxed by Spinks, who did not tire throughout the bout and had Ali ready to fall in the last seconds of the fight. However, Spinks was stripped of his world title by the
WBC for refusing to defend it against
Ken Norton, instead agreeing to a return bout against Ali to defend his
WBA crown.
Rematch His second match with Ali, at the
Louisiana Superdome on September 15, 1978, went badly for Spinks. A now-in-shape Ali—with better, sharper tactics—rarely lost control, winning back his title by a unanimous fifteen-round decision. Spinks was never given a rematch; Ali retired after the fight (although he came out of retirement a few years later to fight
Larry Holmes and
Trevor Berbick).
Career development Spinks's next fight, his only one in 1979, was at
Monte Carlo, where he was knocked out in the first round by future WBA world heavyweight champion
Gerrie Coetzee. In the following fight, Spinks defeated former world title challenger and European title holder
Alfredo Evangelista by a knockout in round 5. He then fought to a draw in with Eddie López, scored a knockout over Kevin Isaac in May, and, in October, beat the WBC's top-ranked challenger,
Bernardo Mercado, by a knockout in round nine on the undercard of
Larry Holmes vs. Muhammad Ali. His strong performance against Mercado earned Spinks a title match against
Larry Holmes. In Spinks's only fight in 1981, on June 12 and what would be his last opportunity to win the heavyweight title, he took multiple punches without responding in the third round and the referee stopped the fight.
Move to cruiserweight It was Spinks's last heavyweight bout for years, as he began boxing in the
cruiserweight division. He beat contender Ivy Brown by a decision in ten rounds, and gained a decision against former and future title challenger
Jesse Burnett in twelve rounds. Spinks was due to face the World Cruiserweight number one
David Pearce, but the fight was called off on 24 hours notice after the fighters had both weighed in, due to the BBBoC stance on Pearce fighting abroad in the newly formed Cruiserweight division. When his brother Michael Spinks defeated Larry Holmes in a controversial upset for the IBF heavyweight championship in 1985, they became the only brothers to have held world heavyweight championships. They kept the distinction until the
Klitschko brothers became champions two decades later. In the 1980s Leon Spinks competed in several boxer vs. wrestler matches in
New Japan Pro-Wrestling (NJPW), including losing by submission to
Antonio Inoki. In 1986 Spinks earned his last championship opportunity, fighting
Dwight Muhammad Qawi for the WBA cruiserweight championship. Qawi had been defeated by Michael Spinks three years earlier for his WBC light heavyweight championship. However, Leon lost by TKO in the sixth round. Spinks retired at age 42, after losing an 8-round decision to Fred Houpe in 1995, who was coming off a seventeen-year hiatus. ==Professional wrestling career==