The Horse Soldiers

The film marked the beginning of mega-deals for Hollywood stars. John Wayne and William Holden received $775,000 each, plus 20% of the overall profits, an unheard-of sum for that time. The final contract involved six companies and numbered twice the pages of the movie's script. The film, however, was a financial failure, with no profits to be shared in the end.

A long-time alcoholic, John Ford was ordered by his doctor to abstain from drinking or he would surely die from its effects. Even though he was notorious for his stubbornness, Ford obeyed the physician's orders. Still, the absence of drink caused him to treat his cast and crew rougher than usual. The one who usually got the worst treatment, drink or no drink, was John Wayne, and he got it good on set. Ford demanded that Wayne also abstain from drink, even though he had no such orders from his physician. Wayne begged producer Martin Rackin to get him away from Ford's omnipresent gaze, if only for a brief moment. Rackin obliged and lied to Ford, telling him that Wayne's teeth were beginning to show up yellow on film and that he needed to take both Wayne and William Holden to New Orleans to have their teeth cleaned. So the drunken trio spent a roaring night in the Crescent City, returning to a furious Ford, who knew through his spies exactly how many bars they had visited.

During filming of the climactic battle scene, veteran stuntman Fred Kennedy executed a fall from a horse improperly, broke his neck and died. According to fellow stuntmen, Kennedy had broken his neck two years earlier, but it had healed. He had appeared in several films directed by John Ford and the director was greatly affected by Kennedy's death. After the incident Ford halted filming and immediately moved the production back to Hollywood. The film was scripted to end with the triumphant arrival of Marlowe's forces in Baton Rouge, but Ford "simply lost interest" after Kennedy's death. He ended the film with Marlowe's farewell to Hannah Hunter before crossing and blowing up the bridge.

John Ford made sure to pay the black extras in Louisiana and Mississippi the same pay as the white extras, raising a few eyebrows in the Southern communities.

Dr. Erastus Dean Yule, the real-life Union surgeon on whom William Holden's character Maj. Hank Kendall was based, actually did volunteer as depicted to stay behind and be taken prisoner by the Confederates along with the Union soldiers who were too seriously wounded to ride. However, this took place before the notorious Andersonville POWcamp existed; prisoner exchanges were still routine, and he was exchanged in due course after a few months.