The 26-year-old from Markham, Ont., Overcame a rough start and finished third with a personal best 9.89 seconds.
Lamont Jacobs of Italy took the gold in 9.80 seconds, followed by American Fred Kerley in 9.84 seconds. The three medalists achieved personal bests.
It is Canada’s first track and field medal at the Tokyo Olympics. It is also the final piece of equipment in the event for De Grasse, who won bronze in the 100 at the 2016 Olympics and 2019 world championships.
Two hours earlier, De Grasse had run 9.98 to finish second in his semi-final and seventh overall.
De Grasse is the first Canadian to step onto the medal podium in Tokyo. Led by swimming superstar Penny Oleksiak, the women had won Canada’s previous 13 medals.
De Grasse will have a day off before returning to the track for the 200 heats and the semi-final on Tuesday. He won silver in the 200 at the 2016 Olympics and 2019 world championships.
There was no net favorite in the men’s 100m this year with Usain Bolt retiring. The Jamaican superstar and world record holder (9.58) won gold and silver in the 100 and 200 in Beijing, London and Rio, and what the media dubbed his “bromance” with colleague Puma De Grasse was an entertaining story in Rio.
American Christian Coleman, reigning 100-meter world champion and sprinter considered De Grasse’s biggest challenge in Tokyo, is serving a doping suspension until May next year.