Sullivan competed in 1000 metre, 1500 metre, and mile events and represented Canada. His personal best times are 3:31.71 for the 1500 (set in June 2000) and 3:50.36 for the mile. He is the former Canadian record-holder for the indoor 3000 m, 7:40.17 (set February 9, 2007). His best Olympic showing is a fifth-place finish at Sydney. In 2005, he left his longtime Michigan coach, Ron Warhurst, to train under the coaching of Julie Henner. In the 2008 Summer Olympics, Sullivan reached the semi-finals of the 1500 metre but failed to qualify for the final. Sullivan was also a torchbearer for the 2010 Winter Olympics, carrying the torch into Brantford.