De Santis had a stint in the National Professional Soccer League with the short lived expansion franchise the Toronto ThunderHawks during the 2000-2001 winter indoor season.
De Santis represented Canada at the 1987 Pan American Games and 1987 FIFA World Youth Championship.
He made his senior debut for Canada in a March 1988 friendly match against Peru, in which he immediately scored his first (and only) goal.
In his first season as head coach he won the Montreals second League Championship beating Seattle Sounders 2–0.
After a poor record to start the 2008 season, De Santis stepped down as head coach of the Impact and was replaced by John Limniatis on June 13, 2008.