Center John Mahaffy spent parts of three seasons with the Montreal Canadiens and New York Rangers in the 40s. The 5'7" sparkplug was a quick skater who could make plays in the offensive zone in a pro career spent mostly in the minors and senior leagues.
The Montreal native played with the junior and senior Royals in his hometown. He also spent the 1938-39 season in Britain with the Streatham hockey club. During the 1942-43 season Mahaffy hit the 20-goal mark for the Montreal Royals and notched seven points in nine games when recalled by the Habs.
In October 1943, Mahaffy was one of several player loaned by Montreal to the New York Rangers. Playing on a line with Fern Gauthier and Ossie Aubuchon, he registered 29 points in 28 games. The next year Mahaffy excelled on the Pittsburgh Hornets of the AHL and was summoned to play one playoff game for the Canadiens.
Beginning in 1945-46, Mahaffy settled in as a top offensive producer in the AHL. He topped the 20-goal mark five straight years and recorded a personal best 83 points for the Philadelphia Rockets in 1947-48. The veteran pivot retired in 1952 after spending one year with the QSHL's Shawinigan Cataracts.