Sullivan graduated from the University of Toronto with a Bachelor of Science degree in 1973.
From February 1974 to November 1984, Sullivan worked for Canadian Broadcasting Corporation (Canadian Broadcasting Company) where he was radio master control operator. From 1984 until his election to the House of Commons in 2011, Sullivan was a national representative for the National Association of Broadcast Employees and Technicians (NABET) and later the Communications Energy and Paperworkers (Committee on Ethics and Professionalism) where he worked with Canadian Broadcasting Company, Sun Media and Torstar newspapers. Sullivan ran as the NDP’s candidate 2008 federal election.
He was defeated by Liberal incumbent Alan Tonks by 6,430 votes.
In 2011 he tried again, this time defeating Tonks by 2,580 votes. He served as the NDP’s Deputy Critic for Housing and Disability Issues.
In the 2015 election, Sullivan was defeated by Liberal candidate Ahmed Hussen by 7,622 votes.
He was a New Democratic member of the Canadian House of Commons from 2011 to 2015 who was elected to represent the Toronto riding of York South—Weston.