During World War II, more than 19,000 Army Soldiers trained at the Military Intelligence Training Center, Camp Ritchie, Maryland, which was run by the War Department's Military Intelligence Service. When the war ended, however, the school was phased out, leaving the Army without a general intelligence school. In October 1945, the Army Ground Forces decided to activate an intelligence school at Fort Benning, Georgia to alleviate the gap. The new school was built on lessons learned during the war, which had shown that few men were ready to assume the staggering jobs of intelligence activities in modern war.

Only one month after its establishment, the school moved to Fort Riley, Kansas, to operate under the administrative purview of the Commandant, The Cavalry School. The new Intelligence Department opened on July 1, 1946. Later that year, on November 1, the Cavalry School dissolved and the Army General School was established. The Intelligence Department continued to teach officers and enlisted combat intelligence specialists and S-2 and G-2 personnel for battalion, regiment, and division staff. The department was called the "first institution of its kind organized within Army Ground Forces."

The Intelligence Department had three divisions: (1) Aerial Reconnaissance for photo interpretation and air intelligence; (2) General Subjects for general intelligence, Army extension courses, and training literature; and (3) Order of Battle and Interrogation of Prisoners of War with an additional section for exploitation of enemy documents. Although the Intelligence Department sought a faculty comprised of combat-experienced officers with extensive intelligence experience, turnover was high due to the army's post-war drawdown and readjustment of its personnel.

The Army General School also taught a six-week course in reconnaissance, scouting, and patrolling, upon completion of which officers rotated into a 12½-week Officers' Intelligence Course through the Intelligence Department. Graduates of this course were considered qualified as G-2s or S-2s. For enlisted personnel, separate seven-week courses trained photo interpreters and interrogators and analysts. An Aggressor Center was even established to provide an enemy force for training realism. The curriculum, however, focused on training graduates to act as instructors on the assumption that, in the event of an emergency, the Army would face an immediate need to train large numbers of personnel.

The emergency anticipated by the Intelligence Department planners came in June 1950 when North Korean forces attacked the Republic of Korea. As intelligence specialists graduated from the Intelligence Department, they shipped off to MI units supporting tactical forces in South Korea. Detachments of MI specialists, Counter Intelligence Corps, and Army Security Agency personnel were attached to each division. Despite the best efforts of the Department, the Army found peacetime intelligence training had been inadequate. This inadequacy would prove the final impetus to fix the problem.

Immediately following the Korean War, MI experienced rapid growth in personnel and organizational structure, as well as a greater emphasis on professionalism, human intelligence, and integrated training. Some of the Army's efforts at creating standardized training and retaining experienced personnel in peacetime took place at Fort Holabird, Maryland, where the Army had been teaching counterintelligence since 1945. As early as August 1954, human intelligence and geographic area (called Field Operations Intelligence at that time) students began training side-by-side with CI students, leading to a redesignation as the Army Intelligence Center under the direct control of the Assistant Chief of Staff, Intelligence.

It was not until almost a year later, however, on May 1, 1955, that the Army consolidated CI, combat intelligence (order of battle techniques, photo interpretation, POW interrogation, and censorship), and area studies at the U.S. Army Intelligence School (USAINTS) at Fort Holabird. Intelligence training at Fort Riley transferred to Fort Holabird, essentially centralizing all intelligence training (except attachés and signals intelligence) at one location.