Marvelous Marvin Hagler (born Marvin Nathaniel Hagler; May 23, 1954) is an American former 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 undisputed middleweight champions at 78%. At six years and seven months, his reign as undisputed middleweight champion is the second longest of the last century, behind only Tony Zale, who reigned during WWII. In 1982, annoyed that network announcers often did not refer to him by his nickname, "Marvelous", Hagler legally changed his name to "Marvelous Marvin Hagler."