While the units assigned to the 155th ABCT vary in seniority, the brigade itself traces its lineage to 16 March 1951 when it was constituted in the Mississippi Army National Guard as the Headquarters and Headquarters Company (HHC) of the 108th Armored Cavalry Group, before being organized and federally recognized on 12 April 1951, based at Tupelo.

[3] The 155th Armored Brigade was mobilized for the Gulf War on 7 December 1990, but remained stateside and was demobilized on 14 May 1991.

The Enhanced Separate Brigades receive specialized training and higher priority than other National Guard units for personnel, equipment and other resources during peacetime.

The brigade deployed to Iraq in support of Operation Iraqi Freedom III from August 2004 to January 2006.

[7][6] In March 2018, the 155th left for a three-month training period at Fort Bliss with the 177th Armored Brigade, prior to a nine-month deployment to support Operation Spartan Shield[8][9] from Camp Buehring in Kuwait.