In 1986 McMahon injured his spine in an automobile accident—and quickly resumed his athletic pursuits. From 1986 to 1995 McMahon played for provincial, national, and state (US) wheelchair rugby teams, leading the Atlanta Rolling Thunder to two National Championships appearances.
McMahon has competed in two Paralympics. He placed first (1996) and fifth (2000) in the marathon, sixth (1996) and eleventh (2000) in the 5000m, and seventh (2000) in the 1500m.[1][2]
McMahon lives in Pawleys Island, SC. He was educated at Carleton University and is the co-founder of Screen 5ive media. He is married to Ann Marie with whom he has a daughter, Connor.