Reidar was awarded the Medal of Honor for action near Ronssoy, France, 27 September 1918. His citation reads, "In the face of heavy artillery and machinegun fire, he crawled forward to a burning British tank, in which some of the crew were imprisoned, and succeeded in rescuing 2 men. Although the tank was then burning fiercely and contained ammunition which was likely to explode at any time, this soldier immediately returned to the tank and, entering it, made a search for the other occupants, remaining until he satisfied himself that there were no more living men in the tank."