Marvin Hagler (born Marvin Nathaniel Hagler; May 23, 1954), also known as Marvelous Marvin Hagler, is an American former professional boxer who competed from 1973 to 1987. He reigned as the undisputed middleweight champion from 1980 to 1987, making twelve defenses of that title, and currently holds the highest knockout percentage of all undisputed middleweight champions, at 78%, while also holding the second longest unified championship reign in boxing history at twelve consecutive defenses.