Corporal Oswald was a member of Company B, 1st Battalion, 9th Infantry Regiment, 2nd Infantry Division. He was seriously wounded in action by the enemy in South Korea on 15 August 1950 and returned to duty on 11 October 1950. He was taken Prisoner of War when his company was overrun during the withdrawal from Kunu-ri, North Korea, on 30 November 1950 and died while a prisoner on 27 January 1951. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Oswald was awarded the Purple Heart with 2 Oak Leaf Clusters, the Combat Infantryman's Badge, the Prisoner of War Medal, 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.