Norway's Braaten Oystein, who was 10th at the event's Olympic debut in Sochi, took gold with the top mark of 95.00, while American Nick Goepper earned silver with a score of 93.60 to improve on his bronze-medal performance in 2014.
Beaulieu-Marchand, 23, landed a triple on the final feature in his best run, the second of three at the Phoenix Snow Park, to secure a spot on the podium.
"I just can't believe it, it's amazing," Beaulieu-Marchand told CBC sports. "I just landed a run I wanted to land.
"I wanted to show the world what I am capable of on my skis and I did. The medal is just a bonus. Medal or no medal, I'm just so happy."
James Woods of the U.S. scored 91.00 to finish fourth.
'Unreal' day for Harle
Teal Harle, 21, of Campbell River, B.C., put down a run of 90.00 to finish fifth in his first Olympics.
"Today was unreal. I've definitely surpassed every expectation I had for the Games," said Harle, who won the last Olympic qualifying event to secure his spot in Pyeongchang.
"Going into it, my goal was just to land a run in qualifications and I made it to finals, so that was insane. It took me three tries, but I landed a clean run in finals. I couldn't be happier with how today went."
Evan McEachran, 20, of Oakville, Ont., landed an 89.40 for sixth. The youngest member on Canada's freestyle team earned his first-ever World Cup podium this season and was appearing in his first Winter Games.
In his first Olympics, Alex Bellemare of Saint-Boniface, Que., finished outside of the top 12 in qualifying and did not advance to the final.
Earlier Sunday, Beaulieu-Marchand qualified third for the final with a run of 94.20, while Harle qualified sixth at 91.20, and McEachran 11th at 87.80.
Beaulieu-Marchand was the lone Canadian to compete in Sochi, where he finished 12th.