Hamelin broke into success early at the 2003 World Junior Short Track Championships where he won silver medals in the 500 m and the 1500 m races, following up with a bronze in the 5000 m relay. He built on this success at 2005 World Championships, there he won a gold in the 5000 m relay and a silver in the 500 m. His success continued at the worlds by winning gold in the 3000 m, gold in the 5000 m relay and bronze in the 1000 m at the 2006 World Championships. He finished 4th place at the 2006 Winter Olympics in the 1500 m event but received a silver medal as part of the men's 5000 m relay squad. Hamelin is the former world record holder in the 1000 m.