Kotsenburg's soulful first run in the finals ended with a score of 93.50 that held up over the next 30 minutes as the rest of the field's dozen riders failed to catch the laid-back Couer d'Alene, Idaho, native, who peppers his interviews with "whoas" and "gnarly" and often refers to himself as "your boy."
Staale Sandbech of Norway grabbed silver while Canadian Mark McMorris, who nearly missed the finals because of a broken rib, surged to bronze as slopestyle provided an electric Olympic debut.
Kotsenburg soared through the sun-splashed Caucasus Mountains and looked as if he were cruising down the hill with his buddies even as he soared off ramps that are the equivalent of leaping out of three three-story buildings in the span of 15 seconds.
His signature moment - when he leapt off the second ramp, unveiling a new trick that impressed the judges and drew oohs from the packed stands.
Kotsenburg got the U.S. off to a golden start in what should be a competitive race at the medal table.
"I can't even describe the feeling," Kotsenburg said. "It's so cool."
In another victory, the U.S. women's hockey team is also celebrating on Saturday. The team won its first game, defeating Finland 3-1.
The second medal for Team USA was in the freestyle skiing category. Hannah Kearney took bronze in the women's moguls finals event. Sisters Justine and Chloe Dufour-Lapointe from Canada took gold and silver, respectively.
- Men's Slopestyle (Snow Boarding) -- Gold: Sage Kotsenburg (USA) | Silver: Staale SAndbech (NOR) | Bronze: Mark McMOrris (CAN)
- Women's Group A Game 1 (Hockey) -- USA 3 vs. Finland 1
- Women's Skiathlon (Cross-Country) -- Gold: Marit Bjorgen (NOR) | Silver: Charlotte Kalla (SWE) | Bronze: Heidi Weng (NOR)
- Women's Group A Game 2 (Hockey) -- Canada 5 vs. Switzerland 0
- Men's Singles Run (Luge) -- TBA
- Men's 10KM Sprint (Biathlon) -- Gold: Ole Einar Bjoerndalen (NOR) | Silver: Dominik Landertinger (AUT) | Bronze: Jaroslav Soukup (CZE)
- Team Ice Dance Short Dance (Figure skating) -- TBA
- Team Ladies Short Program (Figure Skating) -- TBA
- Men's Singles Run 2 (Luge) -- TBA
- Men's Normal Hill Individual Qualification (Ski jumping) -- TBA
- Women's Moguls Finals (Freestyle skiing) -- Gold: Justine Dufour-Lapointe (CAN) | Chloe Dufour-Lapointe (CAN) | Bronze: Hannah Kearney (USA)
- Team Pairs Free Skating (Figure Skating) -- TBA
The Associated Press contributed to this report.