O'Toole was the head coach of the Fairfield Stags men's basketball team from 1998 to 2006 where he compiled a 112–120 record.

While at Fairfield, he was also recognized by the state of Connecticut for implementing a reading program designed to promote the importance of academics and athletics that reached more than 65,000 kids.

O'Toole had also been an assistant coach for the Fordham Rams (1988–89), Army Black Knights (1989–90), Iona Gaels (1990–91), Syracuse Orange (1992–95), Duke Blue Devils (1995–97), and Seton Hall Pirates (1997–98).

O'Toole earned the Patrick Burke award in 1983 and 1984, a recognition given by the university to the player who showed the most hustle and determination.

At Archbishop Stepinac High School, he averaged 21 points and seven rebounds per game under Gene Doris, formerly the director of athletics at Fairfield University.