Sullivan played college football for Saint John's for his freshman and sophomore year.
After eleven seasons, in 1970 he became the head football coach for Cooper High School.
In 1979 he led the team to a Midwest Conference (MWC) Blue Division title.
[7][8] In 1992, he had his best season as he finished the year going 9–2 and won the Minnesota Intercollegiate Athletic Conference (MIAC) alongside a trip to the NCAA Division III playoffs.
[9][10] From 2001 to 2018 he served as a volunteer assistant coach under his son for Northfield High School.