Ford had long opposed war and continued to believe that international business could generate the prosperity that would head off wars; when World War II erupted in 1939 he said the people of the world had been duped. Like many other businessmen of the Great Depression era, he never liked or entirely trusted the Franklin Roosevelt Administration. He was not, however, active in the isolationist movement of 1939–41, and he supported the American war effort and realized the need to support Britain with weapons to fight the Nazis. However, when Rolls-Royce sought a US manufacturer as an alternative source for the Merlin engine (as fitted to the Spitfire and Hurricane), Ford first agreed to do so and then reneged. He “lined up behind the war effort” when the U.S. entered in late 1941, and the company became a major component of the “Arsenal of Democracy.”

Following a series of strokes in the late 1930s he became increasingly senile and was more of a figurehead; other people made the decisions in his name. After Edsel Ford’s death, Henry Ford nominally resumed control of the company in 1943, but his mental strength was fading fast. In reality the company was controlled by a handful of senior executives led by Charles Sorensen and Harry Bennett; Sorensen was forced out in 1944. Ford’s incompetence led to discussions in Washington about how to restore the company, whether by wartime government fiat or by instigating some sort of coup among executives and directors. Nothing happened until 1945, with bankruptcy a serious risk, Edsel’s widow led an ouster and installed her son, Henry Ford II, as president; the young man fired Bennett and took full control.