Provide aviation logistics expertise, planning and material to MAG-12 and its subordinate tactical aircraft squadrons in order to support operational contingencies, theater security cooperation plans, and training exercises in the Pacific Command area of responsibility.

Throughout World War II, HS-12 was attached to both the 1st and 2nd Marine Aircraft Wings and participated in numerous campaigns throughout the Northern Solomons, Leyte, Luzon, and the Southern Philippines.

In July 1956, the newly re-designated Headquarters and Maintenance Squadron 12 (H&MS-12) re-deployed from Korea to its current home base at MCAS Iwakuni, Japan.

In May 1965, H&MS-12 deployed in support of combat operations at Chu Lai and Bien Hoa, Republic of Vietnam.

During December 1989, MALS-12 deployed a substantial detachment to the Philippines in support of MAG-12 operations during the attempted coup.