[1] Originally associated with The Second City's Toronto troupe,[1] he acted both on stage and in television shows such as George Shrinks, Friends and Heroes, Grossology and Getting Along Famously, as well as in guest roles on The Red Green Show, Murdoch Mysteries, Dan for Mayor and Little Mosque on the Prairie.
[1] He previously taught for Humber College's Comedy Writing and Performance program in Toronto, Canada.
His partner was actress Linda Kash, with whom he had three daughters; they lived on a farm outside Peterborough, Ontario.
[1] O'Sullivan died in a car accident near Peterborough on May 18, 2012, at approximately 2:30 p.m. local time.
His car left the road, crossed the shoulder, and struck a parked flatbed truck.