Second Lieutenant McCarthy was a member of the 32nd Infantry Regiment, 7th Infantry Division. He was seriously wounded by the enemy in South Korea on 23 September 1950 and died of those wounds on 29 September 1950.

McCarthy was awarded the Purple Heart, 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.