Spencer O'Brien of North Vancouver won the women's competition, while 19-year-old Mark McMorris of Regina took second place on the men's side behind Finland's Roope Tonteri.
Another Finn, Janne Korpi, took third spot.
O'Brien, 24, posted a score of 93.25 points on her first run and was guaranteed victory before her second go.
She finished ahead of Switzerland's Sina Candrian (81.50) and Australia's Torah Bright (77.50).
O'Brien was the only Canadian in the six-athlete women's final because many competitors withdrew after being unable to take part in Thursday's qualifying as a result of poor weather conditions.
On the men's side, two other Canadians finished in the top 10 in the 20-strong field.
Robby Balharry, a native of Canmore, Alta., was sixth with 77.50 points, while Matts Kulisek of Saint-Sauveur, Que., grabbed 10th spot with 67.50 points.
The snowboarding championships are taking place at the Stoneham Mountain Resort north of Quebec City. They end on the Jan. 26-27 weekend.
The slopestyle event is a new addition to the Winter Olympics beginning with the 2014 Sochi Games.
Some of Quebec's best competitors, including young star Sebastien (Seb Toots) Toutant, weren't able to attend this week because of contractual obligations.
At the request of their sponsor, Toutant, Antoine Truchon and Maxence Parrot will be in Davos, Switzerland for a prestigious big air event.
Toutant and Truchon would have been serious contenders for a medal in the slopestyle and big air events. Truchon won the big air event at a World Cup event in Stoneham last year.
The big air event was to be to be held in downtown Quebec City on Friday and Saturday.
Big air is the only snowboarding event that will be featured at Stoneham that's not part of the Olympic program.
Beginning next Thursday, there will be snowboard cross, parallel slalom and parallel giant slalom events.
Those competitions will feature Canadian snowboarding stars Dominique Maltais, Maelle Ricker, Caroline Calve and Jasey-Jay Anderson.
The world championships include more than 400 athletes from some 40 countries and will allow for some Canadians to secure a spot on the Olympic squad with the Games a year away.
Calve, who had a podium finish in the parallel slalom before the holidays in Italy, already has a spot. So does Maltais, who won the snowboard cross event in Austria at the beginning of the season.
Canada can send a maximum of 24 snowboarders to Russia.