The airfield was opened on 20 September 1941 as the Army Air Force Basic Flying School, one of the fields used by the 30,000 Pilot Training Program.

On Christmas Eve 1944, Castle remained at the controls of his burning B-17 Flying Fortress over Europe while his crew bailed out, then was killed when the aircraft exploded; he was posthumously awarded the Medal of Honor.

On 1 October 1946, the base was put on "minimal operations on caretaker status," with control of the facility under the Colorado Springs AAF.

On 27 June 1949, the Air Force Reserve's 447th Bombardment Group was activated at Castle and equipped with the B-29s formerly of the 93d Bomb Wing.

The wing began aerial refueling operations in October 1950, providing aerial refueling and navigational assistance for the July 1952 movement of the 31st Fighter-Escort Wing from the United States to Japan, the first jet fighter crossing of the Pacific Ocean, during the Korean War.

In August 1990, the wing operated an aerial port of embarkation (APOE) for personnel and equipment deploying to Southwest Asia during Desert Shield.

In addition to aerial refueling, Castle-based KC-135 tankers ferried personnel and equipment, while B-52s deployed to strategic locations worldwide, including Saudi Arabia.

With BRAC closure of Castle AFB confirmed, the 322d Bomb Squadron was inactivated on 3 May 1994 and the wing was placed on non-operational status.

Part of the decision criteria on which bases to close at that time included how well the local community supported its airmen.

Unfortunately, a local Home Owner's Association had just defeated a proposed new base housing project for Castle AFB.

(citation needed) On 1 June 1992 the 93d was relieved from assignment to SAC and was reassigned to the newly formed Air Combat Command (ACC).

As of 2008, local government plans to convert the dormant facility to civilian commercial use has become an active political issue.

[citation needed] It has been identified as the preferred location for the central maintenance facility of the proposed California High-Speed Rail system.

In 2011, Google leased 60 acres (24 ha) in order to test the development of their new project, the self-driving car,[13] which has become Waymo.

Project Loon was a program that creates an aerial Wi-Fi network, using balloons to loft relay equipment to high altitude.

[13] In 2021, Merced County completed a $2.1 million expansion project of the automotive research and testing complex located at Castle (pictured).

Known as TRC—California, the site includes a 2.2-mile oval test track, a one-mile city course and two large vehicle dynamics areas.

The rail district will enhance the ability of agricultural producers, manufacturers and other enterprises from throughout the San Joaquin Valley to quickly and efficiently ship and receive products via the BNSF railroad mainline, which runs adjacent to the site.