Arriving in France with the 155th Infantry in August 1918, he was later assigned to Company A, 356th Infantry, 89th Division. Only days before the Armistice, he volunteered for a mission with Sergeant M. Waldo Hatler to swim across the Meuse River near Pouilly-sur-Meuse to get behind German lines and gather information about troop strength and deployments. They were able to gather the needed information; however, returning across the river, Barkley was "seized with cramps and drowned". (This is the exact wording from his citation, duplicated below.) Sergeant Hatler survived to bring the information back to their unit.