The opportunity to break free from the grip of that Puritan environment came unexpectedly in 1942 when he enrolled in the American Field Service, a voluntary health service organized during the Second World War. Trained as an ambulance driver, he took part in the Battle of El Alamein. He subsequently joined the invasion of Italy where, in Abruzzo, he continued working as an ambulance driver also helping civilians injured by the war. In May 1945 he entered the Bergen Belsen concentration camp just after its liberation. He spent a whole month there, taking part in a mammoth aid mission.
In response to Belsen with its pile of corpses and then the faces of suffering civilians, Congdon discovered that painting, understood as the total giving of oneself, was his life’s vocation. Congdon was one of the few American artists of his generation, if not the only one, to have first-hand experience of a European tragedy that crossed the ocean to make its mark on the canvasses of his colleagues Pollock and Rothko.The war over, Congdon returned to America but not to Providence, knowing only that he wanted to abandon the rigid discipline of New England and dive into the complex and throbbing life of New York. Constantly traveling back and forth between America and Europe, between New York and Naples, he created his most powerful and successful works of those years, which were the beginnings of his very personal pictorial language.