Kronk began to take fame during the late 1970s, when boxers like Thomas Hearns, Hilmer Kenty and others trained there. In 1980, Kenty became Kronk's first world champion, and Hearns followed him as world champion months after. Milton McCrory, another Kronk fighter, won, in 1983, the WBC's world Welterweight title that had been vacated by Sugar Ray Leonard, Jimmy Paul beat Harry Arroyo for the International Boxing Federation's world Lightweight title in 1985, and Duane Thomas, another Kronk fighter, beat John Mugabi for the WBC's world Jr. Middleweight title in 1986. McCrory's brother, Steve McCrory, was also a world champion.
During the 1990s, Kronk opened a second gym, this one in Tucson. A new host of fighters who would later become world champions too arrived at Kronk, among them Gerald McClellan, and the gym began to sell Kronk merchandise through catalog sales.
Among the many world champions who have also trained there at least once during their careers , are Wilfredo Benitez (Benitez trained in the one at Tucson), Hector Camacho, Julio Cesar Chavez, Naseem Hamed, Evander Holyfield, and Lennox Lewis.