Constituted 23 April 1959 in the California Army National Guard as the 49th Administration Company and assigned to the 49th Infantry Division
Organized and Federally recognized 1 May 1959 at Alameda.
Reorganized and redesignated 13 January 1974 as the 49th Personnel Service Company and relieved from assignment to the 49th Infantry Brigade
Location changed 16 December 1988 to Fairfield; on 1 March 1994 to Richmond Expanded, reorganized, and redesignated 1 October 1994 as the 49th Personnel Services Battalion and the 79th Personnel Service Detachment (79th Personnel Service Detachment - hereafter separate lineage)
Location changed 1 September 1995 to Sacramento