The brigade's lineage dates back to 1919, and it had a long and decorated history when designated as the supply command of the 1st Cavalry Division.

Having seen service in every major conflict of the 20th century in support of its parent division, the unit was not designated as the 15th Sustainment Brigade permanently until 2005.

In February 2008, the brigade was reassigned to the 13th Sustainment Command (Expeditionary), ending almost a century of association with the 1st Cavalry Division.

What is now the 15th Sustainment Brigade, and its previous incarnations, have earned 17 campaign streamers, as well as numerous awards, mostly for service during the Vietnam War.

In addition, Company A, 125th Brigade Support Battalion (formerly with 3rd BCT), in conjunction with the inactivation of 3rd BCT, completed a high-visibility project: Company A produced the first Redistribution Property Accountability Team (RPAT) yard in the continental US, which gives commanders a clear picture of property redistribution, especially during a unit's closure.

[4] On 20 October 1967, the Brigade was inactivated after providing support to units in Vietnam, only to be reactivated on 21 September 1968 at Fort Lewis, Washington.

The Brigade later inactivated at Fort Lewis on 21 March 1973 having received campaign credits for its support for Counteroffensive Operations (Phase II and III) in Vietnam.

The history of the organization can be traced back to 1919 when one of its present units, the 15th Forward Support Battalion, existed as the 615th Motor Transport Company.

This was a large scale search of areas under the jurisdiction of the US II Corps which, according to the US Army, saw 5,400 enemy killed and 2,000 captured.

After intense fighting in Hue, the division then moved to relieve US Marine Corps units besieged at the Khe Sanh combat base in Operation Pegasus through March 1968.

[7] In the autumn of 1968, the 1st Cavalry Division relocated south to the III Corps Tactical Zone northwest of Saigon, adjacent to a Cambodian region commonly referred to as the "Parrots Beak", due to its shape.

In addition, Support Command received three Meritorious Unit Commendations and four Republic of Vietnam Cross of Gallantry awards throughout the deployments.

[6] The 15th Sustainment Brigade was the first element of the 1st Cavalry Division to return to Iraq and assumed control for logistics in the Baghdad area of operations in July 2006.

[6] It had sustained several casualties during its tour in the country, including a mortar attack that killed two soldiers and injured five more in October 2007.

These activities include testing new systems for use during deployments,[13] remodeling infrastructure around the fort,[14] and training on personal safety.

[17] Another story was written for defenselink.mil, the press service for the United States Armed Forces in March 2007 about soldiers of the brigade and how they react to the desert climate of the country, having to cope with sandstorms and other issues.