Granheim's background is mountain sports, with a particular focus on steep skiing. Among other things, he has climbed Mount Everest in one day and skied as the first person down the mountain's north face. A decade after Everest, he became the first Nordic climber to summit all 82 peaks in the Alps, a project that was awarded the title Adventurer of the Year.
As an athlete/adventurer, Granheim has always had a camera with him. He has, among other things, been on both sides of the lens for National Geographic and published reports in more than 25 countries from his various adventures. After he retired, he started a photographic project focusing on the high mountains. His work with mountains has been shown at the Munch Museum and has been purchased by Bærum municipality's art collection.