Captain Simpson was the pilot of a F-84E Thunderjet fighter with the 523rd Fighter Escort Squadron, 27th Fighter Escort Wing. On 21 January 1951, while on a combat mission, his flight of four F-84s was attacked by 12 MiG-15s. His aircraft was hit and he bailed out but was killed. His remains were recovered.

Simpson was awarded the Purple Heart, the Korean Service Medal, the United Nations Service Medal, the National Defense Service Medal and the Republic of Korea War Service Medal.