The Second Cavalry arrived in France in April 1918 as part of the American Expeditionary Forces (AEF). Due to the highly static nature of trench warfare on the Western Front, the regiment primarily performed military police, courier, and reconnaissance duties, though a provisional squadron later operated as the last horse-mounted combat element of the U.S. Army to engage the enemy in battle.
The regiment participated in several major Allied offensives, including the Aisne-Marne and Oisne-Aisne campaigns. During the Saint-Mihiel Offensive in September 1918, the regiment performed critical reconnaissance and security operations that assisted in the reduction of the German salient. Immediately following this action, the regiment was deployed to the Meuse-Argonne sector, where the Provisional Squadron, 2nd Cavalry, secured the left flank of the advancing American forces and conducted mounted reconnaissance behind German lines during the final major offensive of the war. The regiment's contributions to the Allied victory were recognized with the addition of three campaign streamers to the regimental standard.
Operating horse cavalry against industrialized weaponry, such as heavy artillery, machine guns, and concertina wire, presented unprecedented tactical challenges. Despite these obstacles, the 2nd Cavalry effectively exploited gaps in retreating enemy lines where motorized vehicles could not traverse the heavily shelled, muddy terrain. This demonstrated that, under specific conditions, mounted troops still possessed unique and valuable mobility advantages.
Following the armistice in November 1918, the regiment marched into Germany as part of the Allied Army of Occupation. Stationed in the Coblenz bridgehead region, the troopers conducted occupation patrols, guarded critical infrastructure, and maintained civil order. The regiment continued these peacetime stabilization duties until their eventual return to the United States in the summer of 1919.