Mike DeJohn came from a family of boxers in Syracuse, New York. His brother, Joey, was a popular middleweight in the 1950s, as had been his brother Ralph in the late 1930s. Another brother, Johnny, managed Mike for the better part of his boxing career. Mike gained an early unexpected victory with a first round knockout of Argentine contender Alex Miteff in 1957. An inability to follow up this key victory, and losses to other contenders for the heavyweight title, would plague Mike DeJohn's career. Nevertheless, the Syracuse fighter was among the best punchers of his era, and this was sufficient to beat the majority of his opponents.