The Headquarters, 500th Military Intelligence Service Group, was constituted on June 30, 1952, in the Regular Army and activated on 1 September 1952, in Japan, under the Far East Command. The Military Intelligence Service Group, Far East, was a temporary organization created to help meet the Army's immediate intelligence requirements and the successor to the Allied Translator and Interpreter Section, which has existed since 1942.
In 1957, the United States and Japan signed an agreement to draw down American troop strength in Japan and relocate the Army's Pacific headquarters from Tokyo to Hawaii. As the U.S. Army Command Reconnaissance Activity absorbed part of the large-scale cutback, the functions of the 500th MI Service Group, along with that of the Intelligence Support Center, Pacific, the successor to the U.S. Army Command Reconnaissance Activity, Far East, and the 500th was inactivated.
On 25 March 1961, the 500th MI Group (Collection) was reactivated at Camp Drake, now Camp Asaka, in Japan with a new mission: to carry out all aspects of the HUMINT mission, not just translation and interpretation. For the first time, the U.S. Army had placed a large portion of intelligence responsibilities in the Pacific within a single unit.
Internally, the 500th MI Group was divided into detachments stationed at various locations throughout the Pacific, from Korea to the Philippines and Thailand. These detachments served a dual role of advising and assisting the military in intelligence collection and engaging in limited collection activities themselves.
On 15 December 1965, the headquarters of the 500th MI Corps Group relocated to Ford Island, Hawaii, a move dictated by efforts to reduce expenditures affecting the international balance of payments.
In 1972, the Group relocated to the Helemano Military Reservation. During this time, the 500th MI Group was recognized for its contributions throughout the Pacific area during the Vietnam War and received the Meritorious Unit Commendation for the periods 1968-1969 and 1972-1974. It was unprecedented at the time for a unit not located within a combat zone to receive such recognition.
The 500th MI Group, like the rest of the Army and military intelligence, underwent essential changes in the aftermath of the Vietnam War. The first of these was the reassignment from US Army Pacific to the US Army Intelligence Agency on 1 November 1974. By 1976, the Gold flow was not the overriding issue it once was, and on 15 July 1976, the unit headquarters was relocated back to Japan. This time to Camp Zama in Kanagawa Prefecture, a former Japanese Imperial Army Academy.
On 1 January 1977, the 500th MI Group was reassigned to the new US Army Intelligence and Security Command (INSCOM). As one of INSCOM's regional military intelligence groups, the 500th would, for the first time, be responsible for the entire spectrum of intelligence and counterintelligence functions at Echelons above Corps. To symbolize the breadth of its new mission, the 500th MI Group received the distinctive designation Pacific Vanguard in April 1978.
Throughout its existence, the 500th continued to be recognized for providing excellent products and support to US Army Pacific and its predecessor, the US Army Western Command, and was awarded the US Army Superior Unit Award (1986-1987).
The growth in status and broadening of its mission was symbolized by its re-designation on 16 October 1987 as the Headquarters and Headquarters Company, 500th Military Intelligence Brigade. Despite the major shift in the world of geopolitics in the late 1980s and early 1990s, the 500th elements and personnel continued to be an integral part of INSCOM's growing commitment to US Deployments overseas, including the Gulf War and Operation Uphold Democracy.