Lucas Pinheiro Braathen, who has dual citizenship, impressed in the giant slalom with a fast first run and a controlled second run, which were enough to win gold in Bormio, Italy.
"I rode completely on intuition and with my heart today. That made it possible to become an Olympic champion," says the 25-year-old.
The gold is South America's first medal at the Winter Olympics.
"I hope I can inspire children, so they understand that no matter what they wear, how they look or where they come from, they can follow their own dreams and be who they truly are. Because that is the source of happiness in life."
Marco Odermatt of Switzerland took silver and compatriot Loic Meillard came in third.
Swedish debutant Fabian Ax Swartz was 22nd.
