The Army Seal was used originally during the American Revolution to authenticate documents. It displayed the designation "War Office", which was synonymous with Headquarters of the Army, and the Roman date MDCCLXXVIII (1778) the first time it was used. It remained unchanged until 1947, when the War Office banner was replaced with "Department of the Army" and the date was changed to 1775, the year in which the Army was established. The seal embodies the Army's ideals of loyalty, vigilance, perseverance, truth, courage, zeal, fortitude, remembrance, determination, constancy, achievement, dignity, and honor. The changes were legislated by the National Security Act of 1947, and authorized by Section 3011, Title 10, United States Code.

Prior to the establishment of the "Department of the Army Emblem", there was no official display item to identify the Army. The Seal had traditionally been used to authenticate documents only and was not authorized for public display. In recognizing the need to provide a display item, the Secretary of the Army approved the emblem design as the official emblem to represent the Army on January 29, 1974.