One of the most formidable boxers of his era, Hagler defended his title 12 times before losing to Sugar Ray Leonard in a 1987 split decision.

Hearns staggered against the ropes and fell to the canvas. Slowly, he raised himself, holding onto the ropes, and was on his feet at the count of eight. The referee looked into Hearnss glassy eyes and waved that the fight was over.
Tommys a good fighter, Hagler said afterward, but hes cocky. I had something for him.
Haglers professional career ended after Leonard, who had fought just once in the previous five years, beat him in a 12-round split decision in 1987 at the Caesars Palace outdoor arena. Hagler, who had not lost a fight since 1976, had been the heavy favorite, and he had a special distaste for Leonard, whom he called Mr. Politician and Mr. Middle Class.
He is a phony, Hagler told The Times in 1987. Hes been protected all his life. Besides, if he hadnt become a boxer, he could have done other things. Me? I had nowhere else to go.
But Leonard put on a stunning display of boxing artistry painting with jabs and uppercuts to score an upset.
Hagler announced his retirement in 1988, saying he didnt want to wait for a rematch with Leonard. Over his career, he had fought 67 bouts, winning 62, losing three and fighting two to a draw, the Boxing Hall of Fame said. He had 52 knockouts.
I feel in my heart Im still the champ, Hagler had said after losing his title. I really hate the fact that they took it from me, and gave it to, of all people, Sugar Ray Leonard.