The Corps was activated on January 17, 1942 five weeks after the entry of the United States into World War II, as the II Armored Corps at Camp Polk in Louisiana. When the concept of Armored Corps proved unnecessary, II Armored Corps was re-designated as XVIII Corps on 9 October 1943 at the Presidio of Monterey, California.

The XVIII Corps deployed to Europe on 17 August 1944 and became the XVIII Airborne Corps on 25 August 1944 at Osbourne, St. George, England, assuming command of the 82nd Airborne Division (Major General James M. Gavin) and 101st Airborne Division (Major General Maxwell D. Taylor), as part of the preparation for Operation Market Garden. Prior to this time the two divisions were assigned to VII Corps and jumped into Normandy during Operation Overlord, the Allied invasion of Normandy, as part of VII Corps