Larkin's brother, Stephen Larkin, was also a professional baseball player; he made it to the major leagues for one game with the Reds. Another brother, Byron Larkin, was a second-team All-American basketball player at Xavier University and is the color commentator on Xavier basketball radio broadcasts. Larkin's eldest brother, Mike, was a captain of the University of Notre Dame's football team in 1985. They were all raised Catholic.
