In 2003, he became the second non-American after Martin Buser to win the 1,049-mile Iditarod Trail Sled Dog Race across Alaska, U.S.
The course was altered that year due to lack of good snow cover, and although Sørlie was obviously a skilled musher with a strong dog team, some claimed the win was affected by the new course.
After holding a tight lead for most of the 2005 race, he won, once again amid warmer than average temperatures and subsequent challenging driving conditions.
He and his dogs ran against a very competitive field, including five other previous winners of the Iditarod, and he finished only 34 minutes ahead of second place.
Bjørnar Andersen finished in fourth place, while Kjetil Backen did not mush, but instead acted as team tactician.