Shepherd served in defensive sectors in the vicinity of Verdun. When the American Expeditionary Forces (AEF) was committed to combat in the spring of 1918 to halt a German advance towards Paris, he participated in the Aisne-Marne offensive (Château-Thierry) where he was twice wounded in action at Belleau Wood during the fighting there in June 1918. On July 28, 1918, Marine Corps Major General John A. Lejeune (Marine Corps Base Camp Lejeune, named 1942) assumed command of the 2nd Division. He returned to the front in August, rejoining the 5th Marines, and saw action in the St. Mihiel and Meuse-Argonne offensives (Champagne) where he was wounded for the third time, shot through the neck by a machine gun.