Three-time Olympic champion White, who was due to compete for the first time in three years, hurt his knee in practice.
Double Olympic champion Jamie Anderson led the way on the last day of the Winter X Games in Aspen, Colorado, with her eighth career title, although fellow American Shaun White was missing after withdrawing due to injury.
White, who was due to compete in the men's snowboard superpipe (a larger version of the Olympic halfpipe), said on social media that he hurt a knee in practice in the week before the event, and had not been able to recover on time.
"It’s a difficult decision to make, but just need to give my knee some time to recover and I’ll be back soon," White wrote.
It would have been his first competition on snow in three years since he won gold in the halfpipe at PyeongChang 2018. He attempted to qualify for skateboarding at Tokyo 2020 before deciding to switch back to snowboarding.
Anderson, who has seven snowboard slopestyle X Games wins, took her first triumph in big air after two bronze medals.
The 2018 Olympic silver medallist in the event (behind Anna Gasser) defeated both her Austrian rival and the other 2018 medallist, Zoi Sadowski-Synnott, who were seventh and third respectively in Aspen.
Of her five runs, Anderson scored a 45 and a 44 for her highest two, giving her a score of 89 points.
While runner-up Onitsuka Miyabi of Japan had a higher single-run score – her first-run 47 led the field – her second-best only received a 39, for a total of 86. That 47 score was enough to put her ahead of Sadowski-Synnott (44 and 42 for a total of 86) on a tiebreaker, though.
Anderson's win moves her to within two of the all-time female Winter X Games Aspen record of 10 titles, held by Lindsey Jacobellis.
In White's absence in the superpipe, eyes were on three-time X Games champion and Olympic bronze medallist Scotty James of Australia was the favourite.
But he was pipped to the crown by Totsuka Yuto of Japan, who three years ago was the youngest competitor in the Olympic field.
The 19-year-old Totsuka was one of two Japanese in the top three, with Lausanne 2020 Youth Olympic champion Hirano Ruka placing third.
No scores were awarded by judges, who instead took note of four runs from each athlete and ranked them based on their overall performance.
In the men's snowboard slopestyle final, 2020 Youth Olympic champion Dustry Henricksen of the U.S. took the honours, outperforming national teammate and PyeongChang Olympic champion Red Gerard, who only placed sixth.
Henricksen, in his first X Games appearance, is the first male American to win the event since Shaun White did so 12 years ago.
The freeski slopestyle was won by two-time Olympic medallist Nick Goepper, his fourth X Games title and first in six years, while Marcus Kleveland took the snowboard big air and Henrik Harlaut won the ski "knuckle huck", a free-for-all in which the idea is to be creative and original rather than doing previously-achieved skills.