The American film industry was motivated by a practical patriotism during the First World War which balanced competing desires to win audiences and to be good citizens. It was understood that enlisting in the war effort on the home front would likely benefit the film industry’s long-term interests. Film producers, exhibitors, and distributors all contributed to the war effort. About 20% of movies released in 1917 and 1918 were war related, including D.W. Griffith’s popular epic, Hearts of the World. Over the decades, films featuring the Great War continued to be produced although their stories and themes changed, and movie-making technology allowed for ever more spectacular scenes. First World War films constitute an eclectic batch, difficult to categorize as a genre, worthy of close reading. While their narratives refer to one time period, 1914-1918, interpretation of the films and their reception resonates also with their respective times of production and reception.