In August 1917, Smedberg was promoted to colonel and assigned to command the 305th Infantry Regiment, a unit of the 77th Division. He led this unit through its organization and training at Camp Upton, New York and subsequent combat in France. Smedberg participated in the Oise–Aisne and Meuse–Argonne offensives, and remained in command until October 23, 1918, when he was promoted to temporary brigadier general and assigned to command the 77th Division's 153rd Infantry Brigade.