Private Gus Cousin was assigned to the 1st Armored Regiment, 1st Armored Division. The Division had come ashore at Anzio and along with the rest of the Allied Forces on 22 January 1944, but had been unable to break out of the beachhead. On 23 May 1944, along with the 1st Special Service Force, the Devils Brigade, a break in the enemy lines was forced and a breakout was accomplished.
Private Cousin was killed in action on 26 May 1944. He was interred at Sicily-Rome American Cemetery, Nettuno, Italy, plot J, row 9, grave 32.