An American Hero tells the story of a romantic and cheerful Irish immigrant, who joins the Army and falls in love and marries an American woman before being sent to fight the Second World War. He suffers terrible losses, while his wife joins the war effort at home. They both endure the war, but their battles take heavy tolls. On his return, he rejects the Medal of Honor for simply surviving the worst day of his life. In the end, he learns the depths of his love of family, the sacrifices of heroes, and the meaning of becoming an American.