He became a member of E ("Easy") Company, 2nd Battalion, 506th Parachute Infantry Regiment of the 101st Airborne Division. He went to England in 1944 to participate in Mission Albany, the airborne landing portion of Operation Neptune, the largest amphibious invasion in history, which was the assault portion of Operation Overlord. Malarkey parachuted into France with his unit. Later that day, in a pitched battle, he helped knock out four German 105 mm artillery battery, an action now called the Brécourt Manor Assault, for which he received the Bronze Star for his heroism.