In 1912, Kilbreth was assigned to the
Mounted Service School at Fort Riley, where he was the commander of the Training School for Bakers and Cooks. When the
United States entered World War I in April 1917, Kilbreth was stationed at
Schofield Barracks, Hawaii with the 9th Artillery. He was promoted to
major in May, and temporary
lieutenant colonel the following August. From August 1917 to May 1918, Kilbreth was director of the Department of Firing at the
United States Army Field Artillery School, and he was promoted to temporary
colonel in February 1918. In May 1918, Kilbreth was assigned to duty in France as chief of operations for
First United States Army Artillery, and he was subsequently assigned as First Army Artillery's chief of staff. In October, he was promoted to temporary
brigadier general and assigned to command the 55th Field Artillery Brigade, a unit of the
30th Division. He remained in command through the end of the war in November 1918, and in December was assigned to staff duty at the
American Expeditionary Forces headquarters. In March 1919, he ended his
post-war occupation duty and returned to the United States. Kilbreth received the
Army Distinguished Service Medal to recognize his wartime service. The citation for the medal reads: Kilbreth demobilized at
Camp Shelby,
Mississippi, and was assigned to command the post. In May 1919, he was assigned as deputy commandant of the Field Artillery School at Fort Sill and returned to his permanent rank of major. In July 1919, he received promotion to permanent lieutenant colonel. From 1920 to 1921, Kilbreth was a student at the General Staff College (now the
United States Army Command and General Staff College), and in 1921 he was assigned to staff duty in the office of the
Chief of Field Artillery. Kilbreth retired from the Army in 1922. ==Retirement and death ==