The missions of the units in the Military District of Washington include ceremonial tasks as well as a combat role in the defense of the National Capital Region.

With the dissolution of the District of Washington in 1927, the commanding general of the 16th Infantry Brigade at Fort Hunt became responsible for conducting military ceremonies and administering discipline to service members in the nation's capital.

The United States Army Band, "Pershing's Own," also became an integral part of the command's ceremonial mission during this period.

This regiment, the oldest U.S. infantry unit, was reactivated in 1948 and assigned to MDW to meet the command's tactical commitments and for military ceremonies.

Vint Hill Farms and Arlington Hall Station, both in Virginia, and Walter Reed Army Medical Center in Washington, D.C., were once part of MDW.

In 1980 MDW gained responsibility for the administration and daily operation of Arlington National Cemetery, in addition to the ceremonial support the command has always provided.

Additionally, they provide rotary-wing (helicopter) support to Army leadership and distinguished officials in the National Capital Region.

On 10 June 2010, Secretary of the Army John M. McHugh rescinded MDW's responsibility for the administration and daily operation of Arlington National Cemetery.

Current units commanded by the district include;[3] A Priority Air Transport helicopter was involved in the January 29, 2025 Potomac River mid-air collision.