After near misses at previous Games, the 36-year-old finally topped the podium at her fifth Winter Olympics.
"This feels incredible because this level that all the women are riding at is a lot higher than it was 16 years ago," Jacobellis told reporters.
"So I felt like I was a winner just that I made it into finals, because that's been a challenge every time.
"All these ladies out here have the potential to win and today it just worked out for me that my starts were good, that my gliding was great, and everything just worked for me today."
Jacobellis infamously won silver in Turin at the 2006 Winter Olympics.
The American, who was 20 at the time, looked set to win gold in snowboard cross' Olympic debut after racing into a huge lead with the finish line in sight.
But with victory seeming inevitable, Jacobellis appeared to showboat on the penultimate jump by grabbing her board.
The result was catastrophic. She fell to the ground and watched on in horror as Switzerland's Tanja Frieden sped past to win gold and leave Jacobellis in second.
Despite the disastrous outcome in 2006, Jacobellis said after becoming an Olympic gold medalist that she doesn't feel a sense of redemption.
"I never thought of it that way. That was not in my mind. I wanted to just come here and compete.
"It would have been a nice, sweet thing, but I think if I had tried to spend (time on) the thought of redemption, then it's taking away focus on the task at hand, and that's not why I race."