On September 19, 1917, the Regiment was re-designated as the 121st Field Artillery Regiment and assigned to the 57th Field Artillery Brigade as a part of the 32nd Division. In addition to the 32nd Division, the records indicated the 121st Field Artillery Regiment also supported the 3rd, 47th, 79th, and the regiment distinguished itself in six major campaigns: Aisne-Marne, Alsace, Champagne, Lorraine, Meuse-Argonne, and Oise-Aisne. Along with the General of the Armies John J. Pershing's personal commendation, the regiment received the battle streamer of the French Croix-de-Guerre with Silver Star embroidered Aisne-Marne and Oise-Aisne. The 121st Field Artillery Regiment was demobilized at Camp Grant, Illinois., May 17, 1919.