LeMay Doan - nicknamed "The Cat" - retained the women's 500m title with an overall time of 74.75 seconds.
The German pair of Monique Garbrecht-Enfeldt and Sabine Voelker took the silver and bronze medal positions.
For Garbrecht-Enfeldt, it was more of the same, having come second to LeMay Doan at the world championships, also in Salt Lake City, last year.
LeMay Doan came into the event protecting an unbeaten season's record.
"I was so tense but I am so relieved," she said after the victory.
The 31-year-old world champion showed her intentions when she set a new Olympic record of 37.30 in her first run - a mark just 0.08 seconds outside her own world record.
The world record she set two months ago was the seventh time she had broken the world mark in five years.
LeMay Doan's husband Bart said this result would probably signal the end of her Olympic career.
The win, Canada's first at the Games, meant she avoided the fate of team-mate and compatriot Jeremy Wotherspoon.
The men's favourite over the same distance fell after five strides of the first leg of his final.