Marvelous Marvin Hagler is a retired American professional boxer who was Undisputed World Middleweight Champion from 1980 to 1987. Hagler made twelve undisputed title defenses and holds the highest KO% of all middleweight champions at 78%.

Marvelous Marvin Hagler is a retired American profesIn 1969 Hagler took up boxing after walking into a gym in the town owned by brothers Pat and Goody Petronelli, who became his trainers and managers. In 1973, Hagler became the National AAU 165-pound champion after defeating Atlanta\'s Terry Dobbs.