The six-time world champion had yet to find his full rhythm this season with just one podium in the first four men's singles events coming in the Italian's second-place finish in Winterberg, Germany.
But the 39-year-old was on it from the start in America, recording the fastest times in both runs to finish with a total time of 1:30.599minutes, ahead of home favourite Chris Mazdzer and Austria's Wolfgang Kindl.
"To be quite honest, before the race I toyed a bit with the idea of a podium finish," said Zoeggeler. "But it's really a big surprise that I achieved the top spot in the end.
"My first run was absolutely perfect and in the second I tried to be more cautious. I couldn't have done better.
"The track in Park City is one of my favourites because it's not the start here that is important. It's the sliding."
It takes Zoeggeler to fourth in the overall standings with 336 points, but it is Germany's Felix Loch, fifth in the individual event, who leads with 385 points heading into the Christmas break.
Loch still tasted victory on the final day however, as he teamed up with Natalie Geisenberger, winner of the individual women's event, and the doubles team of Tobias Wendl and Tobias Artl to win the team relay in an overall time of 2:18.546.
The Germans, who lead the overall standings with 339 points, beat USA's Kate Hansen, Mazdzer, Matthew Mortensen and Preston Griffal by 0.582seconds.
Austria with Nina Reithmayer, Kindl, Andreas Linger and Wolfgang Linger finished in third.