Private First Class Underwood was a member of the 8th Cavalry Regiment, 1st Cavalry Division. He was seriously wounded while fighting the enemy in South Korea on 2 August 1950 and returned to duty on 26 August 1950. He was Killed in Action while fighting the enemy in South Korea on 20 September 1950.

Underwood was awarded the Purple Heart with Oak Leaf Cluster, the Combat Infantryman's Badge, 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.