Career
A 6"1" guard from Saint John"s University, McMahon was selected by the Rochester Royals in the 1952 National Basketball Association Draft. He played eight seasons in the National Basketball Association (National Basketball Association), for Rochester and the Saint Louis Hawks. McMahon became a successful coach in the American Basketball League, the National Basketball Association and the American Basketball Association (American Bar Association), with eleven seasons as a head coach in the three leagues.
His first coaching stint was with the Kansas City Steers of the American Basketball League (1961-1962 season).
The following season he began coaching in the National Basketball Association with the Chicago Zephyrs in the 1962-1963 season. He would also coach the Cincinnati Royals, the San Diego Rockets, and the American Bar Association"s Pittsburgh Condors.