The son of a wealthy physician, Emile de Antonio grew up in the tough coal-mining town of Scranton, Pennsylvania, and it made a deep impression on him. His sympathies were always with working-class people (although he was a Harvard graduate, he was at times a dock worker, a peddler, the captain of a river barge and a broker in war-surplus equipment), and his documentaries are decidedly Marxist in philosophy. His most famous film is probably Point of Order (1964), about the Army-McCarthy hearings ten years previously, but his most controversial films would be Millhouse (1971), a scathing indictment of then-President Richard Nixon , and In the Year of the Pig (1968), a radically left-wing perspective on the Vietnam War.
His film In the King of Prussia (1983) was about the Plowshares Eight, a group of Christian anti-war activists on trial for breaking and entering into a weapons plant, where they damaged missile nosecones, poured vials of their own blood onto missile plans, and burned other files. The film starred the actual defendants as themselves.