He slapped the hands of fans that lined the street in Nome to watch him bring in eight dogs off the Bering Sea ice and down the town's main street to the finish line early Wednesday morning. His winning time was nine days, 12 hours.
Ulsom is the third person born outside the United States to win the race, and the second Norwegian. Nic Petit was running in second place, and defending champion Mitch Seavey was in third.
Joar Ulsom of Norway has won the world's most famous sled dog race after a grueling dash across Alaska's rough terrain.
After nearly 1,000 miles (1,609 kilometers), Ulsom came off the Bering Sea ice just outside Nome and ran the last few blocks as a crowd cheered him on. He becomes the third person born outside the U.S. to claim the Iditarod Trail Sled Dog Race.
He picks up about $50,000, a drop from the 2017 winner's earnings of more than $71,000.
The race is suffering financially and has lost a major sponsor in the last year. Organizers have blamed animal rights activists for putting pressure on sponsors.
The Iditarod also has been marked by fallout from its first-ever dog doping scandal. New rules this year made mushers responsible for any positive drug test.