Its mission was defined as: "a territorial agency with appropriate staff designed to coordinate or prepare to initiate the execution of all plans for the employment of Army Forces and installations against enemy action in that portion of the United States lying within the command boundaries.

[2] After 24 December, the command exercised control over Army coast defense, antiaircraft, and fighter assets from Maine through Florida.

[2] This specifically included the states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, Pennsylvania, Delaware, Maryland, Virginia, North Carolina, South Carolina, Georgia and Florida (minus the western half of the Panhandle), as well as the District of Columbia.

[2][3] The initial subordinate commands included First Army, the First and Third Air Forces, and the First, Second, and Third Corps areas.

The 144th Infantry Regiment transferred in from the Western Defense Command in January 1943 and was withdrawn in March 1944.

In August 1945, he was liberated from a Japanese prisoner of war camp and assumed command after he returned to full duty.