 After playing his college football at the University of Kentucky, Stewart joined the CFL's Calgary Stampeders for the 2001 season, playing only one game before being released the following year in the preseason.From 2002 to 2011 Stewart played for the Montreal Alouettes, leading the team in quarterback sacks for four seasons (2003–06).In 2004, he had 21 tackles, 9 sacks and 4 interceptions (returning 2 of those for touchdowns), good enough to make the CFL All Star Team and to win the CFL's Most Outstanding Defensive Player Award.