It was not only the first time the event had ever been staged at the Olympics, it was also the first medal final of the Sochi Games.
The gold medal went to a 20-year-old with long, blonde hair who at last year's world championships finished a distant 20th.
This time, however, he turned in a sensational run as one of the first snowboarders down the challenging course and none of the other 11 finalists could match it.
Staale Sandbech of Norway won the silver medal and the bronze went to Mark McMorris of Canada.
Canadians Max Parrot and Sebastien Toutant, both of whom had been expected to challenge for a medal, finished fifth and seventh.
Kotsenburg arrived at the Rosa Khutor Extreme Park Saturday without having a place in the finals secured. The top eight finishers from Thursday's qualifying earned a spot in the finals and Kotsenburg was not among them.
Instead, he had to place in the top four of the semifinal qualifying early Saturday and he did so with the second-best run.
The slopestyle course consists of a series of rails and jumps on which the contestants perform tricks and each snowboarder gets two runs in the finals. The best of those two runs is the one that counts in the final standings.
The draw sent Kotsenburg out third and his dazzling series of flips and spins was rewarded with a score of 93.50. The next closest score during the first run was the 83.75 given to Sweden's Sven Thorgren, who eventually finished fourth.
Kotsenburg could not improve his score on his second run and he then had to sweat out the performances put in by all the medal hopefuls.
McMorris produced a run that included two triple jumps and when he finished it appeared he might have done enough to pass Kotsenburg. Only the American judge, however, gave McMorris a score of 90 and his average score of 88.75 was not enough.
Sandbech, who was next-to-last to compete, earned a score of 91.75 for the silver medal.
Although there were several flawed runs during the finals, there were no major incidents on a course that originally drew plenty of complaints.
U.S. snowboarding hero Shaun White injured a wrist while training on the course and withdrew from the event to concentrate on the halfpipe competition, where he is two-time defending Olympic champion. Torstein Horgmo of Norway, one of those expected to contend for a medal, suffered a broken collarbone the first day the course was open.
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