Born: Glasgow, Scotland, April 9, 1922.
Brought to Canada when he was one year old and lived in Watrous, Saskatchewan until he was nine when he and his family returned to Scotland because of the great depression. Served with the Royal Air Force in Africa during World War Two. Returned to Canada in 1951 and started refereeing one week after his arrival. Was soon involved in establishing minor programs in Toronto eventually becoming president of the Toronto Minor Soccer Association. Later worked with Steve Stavro in promoting numerous international exhibition games in Toronto. However, it was as the manager of Canada's international teams from 1971 to1982, except for a brief spell in 1975-76 that he became known nationally and internationally. His dedication to making Canada a power internationally won him acclaim, not only here at home, but around the world. Under McMahon, Canada's national teams won international respectability for the first time. In recent years has been a member of the Heritage Committee of The Ontario Soccer Association and a Governor of The Soccer Hall of Fame and Museum until illness forced his resignation in 1999.