Constituted 24 June 1921, in the Organized Reserves, as Headquarters and Headquarters Company, 196th Infantry Brigade, as an organic element of the 98th Division. The unit was organized in Buffalo, NY. Redesignated 30 January 1942 as the 3rd Platoon, 98th Reconnaissance Troop, 98th Division. The unit was ordered to active military service on 9 June 1942, and reorganized 15 September1942 at Camp Breckenridge, KY, as the 98th Cavalry Reconnaissance Troop. Reorganized and redesignated 13 August 1943 as the 98th Reconnaissance Troop, Mechanized. During WWII the unit saw service in the Pacific Theater and occupation duty in Japan as the 3rd Platoon, 98th Reconnaissance Troop Mechanized, of the 98th Infantry Division. The unit was inactivated 16 February 1946 at Osaka, Japan.
Returning to reserve status in 1947, the unit was redesignated 26 February 1947 as the 98th Mechanized Cavalry Reconnaissance Troop and assigned 98th infantry Division, LJSAR, New York State. On 21 February 1949 the unit was reorganized and redesignated as the 98th Reconnaissance Company. On I May 1959, the unit was redesignated as Headquarters and Headquarters Company, 196th Infantry Brigade and allotted to the Regular Army. On 10 September 1965, at Fort Devens, Massachusetts, the 196th was reactivated and redesignated the 196th Light Infantry Brigade. On 15 July 1966 the unit boarded Military Sea Transport ships in Boston and sailed for Vietnam. The brigade landed 14 August 1966 in Tay Ninh City and began combat operation in the III Corps Tactical Zone. The 196th IN Bde conducted Operations Cedar Falls, Dadsen, Lancaster, Attleboro, Junction City, and Benton as a separate brigade. On 25 September 1967, the Brigade became an organic part of the Americal Division and participated in operations Wheeler/Wallowa, Golden Fleece, Fayette Canyon, Frederick Hill, Lamar Plain, Elk Canyon I, and Elk Canyon II. The 196th Infantry Brigade was the last combat brigade to depart Vietnam in June 1972. The Brigade suffered 1,004 KlA's and 5,591 WIA's while fighting in Vietnam.
The Brigade was inactivated on 30 June 1972, in Oakland, CA. The 196th Infantry Brigade was reactivated on 26 May 1998 as a numbered Training Support Brigade, providing dedicated and professional support to Reserve Component Forces throughout the United States Army, Pacific, area of responsibility.
196th Infantry Brigade trains and validates all US Army, Pacific assigned Army National Guard and US Army Reserve forces in accordance with FORSCOM and USARPAC Training Guidance in order to ensure units are fully prepared to deploy in support of Overseas Contingency Operations (OCO) and other operations as directed.