The US Army bears a blue replica of the official War Office seal over a white background. Underneath the seal is a white writing over a red field that reads "United States Army". Underneath is the date 1775, which stands for the year the Army was established with George Washington being the Commander-in-Chief. President Dwight Eisenhower is the one who gave the flag an official status in June of 1956.
There is a lot of history behind the US Army Flag. The concept of this flag appeared in the midst of the Civil War, more specifically when the War Department instructed regiments to inscribe the names of battles on the colors of their country, in other words, on the American Flag. Evidently, the US Army Flag was created to show the Army as a whole, and all their campaigns.