The origins of the hat can be traced to the 1840s when army troops posted in the west happily donned themselves civilian hats. The name started to be used after the 1872–1876 regulations popularized during the American Civil War. During the Spanish–American War the standard central crease on the crown was found to be impractical as it held rainwater from the downpours. Soldiers reshaped the crown to form a pinched "Montana peak." The army officially adopted the peaked design in 1911.
Sir Robert Baden-Powell introduced the hat for the South African Constabulary and the Boy Scouts.
Through the WW1 era, the campaign hat worn by American soldiers was fairly soft. Those worn by the United States Army's General officers had a golden cord around it, whereas other Commissioned officers had a golden-and-black cord around their hat. Field Clerks and Warrant officers, had a silver/black cord, while other ranks had cords in their branch-of-service colors. United States Marine Corps had the Eagle, Globe, and Anchor badge in black at the front of their hats.
By the 1930s the felt was made very stiff with a permanently flat brim. Due to the frequent wearing of helmets in France in World War I, most troops received a copy of the French bonnet du police that became known as the overseas cap. In 1942 the campaign hat ceased to be issued generally, but it was still commonly found in the Pacific theatre for much of the war, and was the trademark of General Joseph Stilwell.