Marvelous Marvin Hagler  (born  Marvin Nathaniel Hagler ; May 23, 1954 – March 13, 2021) [2]  was an American  professional boxer and film actor who competed in boxing from 1973 to 1987. He reigned as  undisputed middleweight champion from 1980 to 1987, [3] making twelve successful defenses of that title, and holds the highest  knockout percentage of all undisputed middleweight champions, at 78 percent, while also holding the  third-longest unified championship reign in boxing history  at twelve consecutive defenses. At six years and seven months, his reign as undisputed middleweight champion is the second-longest of the last century, behind only  Tony Zale , whose reign included several years of inactivity during his service in  World War II . 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