Malarkey, born in Astoria in Oregon (USA), worked for two years after graduating from High School and studied at the University of Oregon for a semester in late 1941.

After the Japanese attack against Pearl Harbor on December 7, 1941, he attempted to engage in the marines but had to abandon due to dental problems.

He tried to enter the U.S. Air Force but he is also forced to abandon because of poor performance in mathematics. He then volunteered in the airborne troops and joined the Easy Company in July 1942 at Camp Toccoa, Georgia, where he specialized as mortar gunner.

Don Malarkey has written his war memoirs: Easy Company Soldier.