Corporal Pacheco was a medic with the Medical Company, 5th Cavalry Regiment, 1st Cavalry Division. He was seriously wounded by the enemy while tending his wounded comrades in South Korea on 18 September 1950 and died of those wounds on 6 November 1950.

Pacheco was awarded the Purple Heart, the Combat Medical 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.