Dorothy Copetti and Stryker Zablocki scored in the third period to help the Canadians win the gold medal.
Caileigh Tiller opened the scoring on the power play in the first period for Canada, who outshot the Americans 30-14.
Sydney Sawyer set the table for two successes for the Unifolié representatives.
Earlier in the day, Czechia defeated Sweden 2-1 to claim the bronze medal.
Canada advanced to the final of the tournament by defeating the Czech Republic in the semi-final on Saturday. The Americans did just as much, beating Sweden 2-1.
Canada