First Lieutenant Madsen was a pilot of a RF-51D Mustang night fighter with the 45th Tactical Reconnaissance Squadron, 67th Tactical Reconnaissance Wing. On 30 October 1951, while on a combat mission, his aircraft received a direct hit by anti-aircraft fire, exploded in mid-air and crashed. He was listed as Missing in Action and was presumed dead on 14 November 1951. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Madsen was awarded the Air Medal with Oak Leaf Cluster, the Purple Heart, the Korean Service Medal, the United Nations Service Medal, the National Defense Service Medal, the Korean Presidential Unit Citation and the Republic of Korea War Service Medal.