The "Mountain Warrior" Brigade, Fourth Infantry Division (Mechanized) was constituted Nov. 19, 1917, in the Regular Army as Headquarters, Seventh Infantry Brigade, an element of the Fourth Division. It was then organized in December 1917 at Camp Greene, North Carolina.

The brigade served valiantly during World War I and earned battlefield streamers for its participation in the Aisne-Marne, Saint Mihiel, Meuse-Argonne, Champagne-1918 and Lorraine-1918 campaigns.

The unit was reorganized and redesignated in March 1921 as Headquarters and Headquarters Company, 7th Infantry Brigade. The unit was inactivated Sept. 21, 1921, at Camp Lewis, Washington. It was redesignated March 23, 1925, as Headquarters and Headquarters Company, 7th Brigade, and relieved Aug. 15, 1927, from assignment to the 4th Division and assigned to the 7th Division. It was relieved Oct. 1, 1933, from assignment to the 7th Division and assigned to the 4th Division. It was redesignated Aug. 24, 1936, as Headquarters and Headquarters Company, 7th Infantry Brigade, and disbanded Oct. 16, 1939.

With tensions rising in the Republic of Vietnam, the brigade was reconstituted Aug. 21, 1963, in the Regular Army as Headquarters and Headquarters Company, Second Brigade, Fourth Infantry Division, and activated Oct. 1, 1963, at Fort Lewis, Washington. During the Vietnam War, the Second Brigade received battlefield streamers for participation in 11 combat campaigns.

After the Vietnam War, the brigade fought the rest of the Cold War while stationed at Fort Carson, Colorado, until it was inactivated in 1989. Subsequently reactivated Dec. 15, 1995, at Fort Hood, Texas, the brigade led the Army's Force XXI experimentation and validation, shaping the force of the 21st Century.

The Mountain Warrior Brigade has participated broadly in operations in both Iraq and Afghanistan. In 2003 and 2005 the 2nd Armored Brigade Combat Team deployed to the Middle East in support of Operation Iraqi Freedom. In late 2006, the brigade moved from Fort Hood, Texas, to Fort Carson, Colorado, and again deployed to Iraq in 2008 and then Afghanistan in 2011. Meanwhile, the 4th Infantry Brigade Combat Team deployed in 2006 to Iraq and in 2009, 2012 and 2014 to various regions of Afghanistan.

In 2015, the 4th Infantry Brigade Combat Team was reflagged as the 2nd Infantry Brigade Combat Team. The brigade returned to Afghanistan in 2016 and 2018 where Mountain Warrior Soldiers served on missions in Kandahar, Bagram, Dwyer and Tarin Kowt in support of the Resolute Support Mission to train, advise and assist Afghan National Defense Security Forces.

The brigade’s proud history includes being one of the most frequently deployed units to Iraq and Afghanistan and being distinguished with three Medal of Honor recipients, the most awarded of any brigade in the Army during recent conflicts.