1913 he completed the Field Officers' Course. He was a student at the Army War College from 1913 to 1914, and was the Director of the War College from 1914 to 1916. World War I Cameron was assigned to command the Maneuver Camp at Fort Benjamin Harrison at the start of U.S. preparation for entry into World War I. He subsequently organized officer training in the Army's Southern Department, and then commanded the 5th Cavalry Regiment. In 1917 he was assigned to command of the 3rd Brigade in the Army's 15th Cavalry Division. When the plan to field Cavalry divisions was dropped in favor of creating all Infantry divisions, Cameron was assigned as commander of the 25th Cavalry Regiment. Cameron was promoted to temporary brigadier general and briefly commanded 78th Infantry Brigade, 39th Infantry Division and 80th Brigade, 40th Infantry Division. From September to December 1917 he commanded the 40th Infantry Division. He was promoted to temporary major general in December 1917 and assigned to command of the 4th Infantry Division. He was the division's first commander, and led it from its organization at Camp Greene, North Carolina through most of 1918, including the Saint-Mihiel Campaign and the start of the Meuse-Argonne Campaign. He is also credited with designing the division's shoulder sleeve insignia. From August to October 1918 Cameron commanded the V Corps, and led it during the latter portion of the Meuse-Argonne campaign. He was relieved after the Battle of Montfaucon, supposedly because V Corps did not accomplish their objective on the first day of fighting, but possibly because he argued with Hugh Drum. (John J. Pershing was attempting to simultaneously command First Army and the American Expeditionary Forces. As First Army Chief of Staff, Drum, then a colonel, was at times its de facto commander. During the Battle of Montfaucon, he pressed Cameron during a phone call, and Cameron told him "you can't talk to me like that." Cameron was of the view that Drum reported the conversation to Pershing, and that it led to Cameron's relief.) In October 1918 he was succeeded at V Corps by Charles P. Summerall, a Pershing protégé, and returned to command of the 4th Division. Later in October Cameron was designated to return to the United States to organize and train additional units for fighting in France, but the end of the war eliminated the need for more soldiers. Post World