The first Territorial Militia was provided for by a system of laws devised by General Stephen W. Kearny, commonly known as the Kearny Code after Kearny occupied New Mexico in 1846.[1] Then in 1851 the first territorial Legislature created the office of Adjutant General and placed the territorial Militia under its jurisdiction.

In 1862, the Territorial Militia, also known as the New Mexico Volunteers, played a decisive role in the defeat of Confederate forces in the Battle of Glorieta Pass. During 1863 and 1864, the Militia was also active in Navajo and other Indian campaigns of the period.

The New Mexico Volunteer Militia was redesignated on 17 March 1897 as the New Mexico National Guard.

After the Spanish–American War began in 1898, volunteer forces were organized, which included Teddy Roosevelt's "Rough Riders." Many New Mexico Guardsmen helped form the 2nd Squadron, 1st United States Cavalry, which served with Roosevelt at the legendary charge of San Juan Hill.

After the war with Spain, units of the New Mexico National Guard were again placed in active service on the Mexican border to pursue Pancho Villa after Mexican forces raided Columbus, New Mexico in 1916. The Guard spent one year on this border duty, hardening themselves to the rough field conditions of the desert southwest.

In 1921, the Guard in New Mexico was reorganized into the 111th Cavalry Regiment, the 120th Engineers, and Battery A, 158th Field Artillery. In 1939, the War Department suggested the 111th Cavalry convert to another branch of service and the officers of the command jointly selected Coast Artillery. In 1940, the 111th was re-designated as the 200th Coast Artillery and the 158th was reorganized as the 104th Anti-Tank Battalion. On 6 January 1940, these units, along with the 120th Engineer Regiment, were called to active duty for what was supposed to be a one-year training period.

In August 1941, the 200th was given notice that it had been selected for an overseas assignment of great importance. At about 0300 hours on 8 December 1941, the 200th went on full alert when the night radio crew picked up commercial broadcasts telling of the Japanese attack at Pearl Harbor, Hawaii.

During the 1983–1989 time frame, the New Mexico Army National Guard began a complete modernization program to gain high technology type units. The 5th Battalion, 200th Air Defense Artillery (Roland) was fielded at McGregor Range (a part of Fort Bliss located in New Mexico). This unit was inactivated in September 1988 due to Federal budget cuts. A complete conversion of Duster battalions to MIM-72 Chaparral battalions was accomplished. A new anti-aircraft missile battalion equipped with the MIM-23 Hawk was put in place at Rio Rancho, New Mexico.

On 1 October 1993, the Headquarters Battery, 2d Battalion, 200th Air Defense Artillery was expanded to form the 2d Battalion, 200th Air Defense Artillery. The battalion was converted, reorganized, and redesignated 15 December 1995 as the 202d Field Artillery, a parent regiment under the United States Army Regimental System, to consist of the 1st Battalion.

In 2005, the 3rd Battalion, 200th Air Defense Artillery, was reorganized as the 1st Battalion, 200th Infantry Regiment.

The 111th Air Defense Artillery Brigade headquarters became the 111th Maneuver Enhancement Brigade headquarters in 2005. Similar to a special troops battalion, its mission was to support units of the Regular Army. The 111th Maneuver Enhancement Brigade headquarters deployed to Guantanamo Bay and Kosovo. On 1 September 2016, the brigade was redesignated, once again, as a sustainment brigade that focuses on providing mission command for combat support and combat service support units.[8] The brigade is designed to operate independently in a theater of operations, in conjunction with other sustainment brigades under the command of a sustainment command (expeditionary), or directly under a theater sustainment command.[9][10] Following the sustainment brigade conversion, the 111th included the 111th Special Troops Battalion, 515th Combat Sustainment Support Battalion, and 615th Transportation Battalion.

In the aftermath of Hurricane Maria, the 115-strong brigade headquarters was sent to Puerto Rico in November 2017 for a month-long deployment supporting relief efforts under Joint Task Force-Puerto Rico.[12] Under the command of Colonel Jamison Herrera, it served as the headquarters for relief efforts in San Juan.

Most recently, the 111th Sustainment Brigade has supported the ongoing COVID-19 response efforts. The 111th has supported this effort by providing Personal Protective Equipment warehousing support, Rapid Response Team support to COVID-19 testing sites, long-term health care facility cleaning, the establishment of alternate care sites, vaccine distribution and administration, and humanitarian support to the communities of New Mexico, the Pueblos, and the Navajo Nation.