During shooting, John Farrow took over direction for a few days when William Dieterle was stricken with a virus infection. Farrow's work is uncredited on screen credits.
John Ireland replaced Wendell Corey who was forced to drop out of the role of William Quantrill due to illness.
Location shooting took place near Gallup, NM, at six different camps. Navajo Indians from a nearby reservation were recruited as extras, and Chief Long Bow, a full-blooded Pueblo Indian, acted as translator.
Alan Ladd and Arthur Kennedy both served in the First US Motion Picture Unit of the US Army Air Forces in World War II.