Aged 17 and 227 days, Gerard handed the US their first gold of the Pyeongchang Games with his slopestyle win, making him the youngest US Winter Olympic champion since 1928.
Gerard, born on June 29, 2000, also set a record for the youngest gold medallist in any snowboarding event that was held previously by Kelly Clark, the 2002 women's halfpipe champion at age 18 years and 199 days.
"I cannot believe it," Gerard said. "I'm shaking right now, maybe from the cold, or the excitement. I don't know. But I'm ecstatic. I can't believe it.
"Just to land a run would have been plenty for me and to get on the podium, but to get first is crazy."
The 17-year-old landed a backside triple cork -- a triple-twisting trick with a flip -- to score 87.16 points on his final run to snatch victory from Canadians Max Parrot, who took silver, and Mark McMorris, who picked up a second bronze after Sochi four years ago.
"I'm super-psyched!" said Gerard, who wants to attend film school for the next two years.
"I'd have to guess people are pretty surprised," Gerard said. "I had a lot of fun and all I really want to do is just land runs."
Gerard was off the pace after the first and second runs, scoring 43.33 and 46.40, before somehow summoning up an enormous last effort.
"After I landed the second jump I was like, 'Come on, don't blow it on the last one, let's just make it through'," Gerard said.
"The wind was really bad and the first two runs it was pretty tough, but we got a nice little break on the third and I'm just happy I got it to land."
- 'Just so happy' -
The only younger individual event Winter Olympic champion than Gerard was Finnish 16-year-old ski jumper Toni Nieminen in 1992.
"It feels incredible. I'm just really happy that I got to land a run and I'm just really excited right now," said the Colorado native, who came fourth in the X-Games last month.
Gerard tried the sport as a toddler then took it up with a passion aged eight when his family moved closer to the snow. He built his own snowboarding training ground with his brother at the back of his family home as his ambitions grew. Seventeen family members are in Pyeongchang supporting him.
"It's definitely crazy having a group of 17 people on the slope run-in, knowing that they are there," he said.
"They helped with everything in the build-up... and they smack me back into place when I get all cocky."
Appearing at an Olympics was top of his career targets after joining the World Cup circuit in 2015. And it lived up to all his expectations.
"It was awesome. I just told myself that I want to land a run and I was a little bummed on my first two runs because I fell a couple of times," he said.
"I'm just so happy that it all worked out."
Canada's Parrot, who won the X-Games Big Air this year in Aspen, Colorado, also had a disappointing first two runs but hoisted himself into silver on his last attempt, and threatened for more.
"I saw Red landing his run," Parrot said. "It was just clean from top to bottom and that's what the judges wanted to see."
Third placed McMorris said the bronze medal was just like winning gold for him following a near-fatal accident 11 months ago. McMorris was fighting for his life after breaking 17 bones and suffering a collapsed lung and ruptured spleen in a snowboarding accident.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)