About Marvelous Marvin Hagler
Marvelous Marvin Hagler was an American professional boxer who competed from 1973 to 1987. He reigned as the undisputed champion of the middleweight division from 1980 to 1987, making twelve successful title defenses, all but one by knockout. Hagler also holds the highest knockout percentage of all undisputed middleweight champions at 78 percent. His undisputed middleweight championship reign of six years and seven months is the second-longest active reign of the 20th century. He holds the record for the sixth longest reign as champion in middleweight history. Nicknamed "The Marv" and annoyed that network announcers often did not refer to him as "Marvelous", Hagler legally changed his name to "Marvelous Marvin Hagler" in 1982. He first entered Vinnie Vecchione's gym (where, unknown to him, Dornell Wigfall trained), but after one week watching, and of nobody speaking to him, Hagler decided to leave for good.
Biography source: Wikipedia. The profile adds birthday-specific historical context from the Celebs Birthday Today editorial database.