He played Tier II Junior "A" for the Wexford Raiders in 1990-91 and major junior for the Belleville Bulls from 1991 to 1995. Undrafted by the NHL, he opted to play college hockey for the St. Mary's Huskies from 1995 to 1998.
Doull played two seasons in the International Hockey League from 1998 to 2000 and then went to Great Britain in 2000 to play for the Manchester Storm. Returning to North America, he played two seasons in the American Hockey League.
Finally in 2003-04 Doull got his NHL chance. Signed as a free agent by the Boston Bruins, he played 35 games for them that season. The Phoenix Coyotes signed him in 2004 and traded him to the Washington Capitals in 2006. It was with the Caps that Doull played his final two NHL games in 2005-06.
He retired in 2006.
Doull played in 37 NHL games and scored 1 assist.