The first US rider to do win the World Cup in a decade, Gwin claimed five out of the seven rounds, and wrapped up the title with one round remaining.
"I am just really happy," stated Gwin. "It was an important race for me. I struggled here last year with a crash and felt good this week, but it was rough, it was definitely a challenge. I don't know, the top part went pretty good, I felt like I was on a good run.
"So I just tried to be smooth at the bottom. I went a bit slower than I would have liked to at the bottom. I am just so happy. I want to thank all the fans and sponsors and everybody. It has been an awesome year. Could not have done it without you all."
Gwin finishes the season with 1558 points, five wins, a third and a fourth. Minnaar, with two wins this season, hung on for second with 1093 points, ahead of Atherton at 1009. Danny Hart jumped over Steve Smith to take fourth, while Smith hung onto the final podium spot.
Brits round out the podium
Meanwhile, while the race for the overall title was out of the question, it was all to play for in the final round, especially with the World Championships just around the corner.
Danny Hart and Gee Atherton were the best of the rest, taking second and third respectively. Danny showed the form we saw earlier this year at Fort William, keeping it pinned right down the rough course to finish just over a second adrift. Gee finished a further 3 seconds back.
Other Brits finishing well included Josh Bryceland in 11th, Marc Beaumont 13th, Matthew Simmons 16th and Joseph Smith in 22nd.