On 11 May 1990, Reuterswärd and fellow climber Oskar Kihlborg became the first Swedes to reach the summit of the Mount Everest, and in 1994 he and Kihlborg became the first Scandinavians to climb the world's fourth-highest mountain Lhotse in the Himalayas. In 1989, Reuterswärd climbed the Pioneer Ridge on the northern peak of North America's highest mountain Mount McKinley.