Hamelin won the 1,500-meter race in a competition that lived up to the wild expectations associated with the sport.
Current world champion Da Woon Sin of South Korea fell during his semifinal heat and 17-year-old Han Tianyu of China, who has not finished better than fourth in any World Cup race this season, wound up with the silver medal.
Viktor An of Russia finished third to win the first Olympic short-track medal for his country since the sport was introduced to the Games in 1992.
It was not the first Olympic medal for An, however. He was born in South Korea and won the 2006 1,500-meter race at the Turin Games as a representative of his native country. An has since become a citizen of Russia.
American J.R. Celski finished fourth in the seven-man final.
Although short-track skating is easily the most unpredictable of all the sports in the Winter Olympics, Hamelin was among the favorites.
He won the 500-meter race in Vancouver four years ago and was part of the victorious Canadian relay team at those Olympics. He also won a silver medal in Turin as part of the relay team.