John Ford suspended location filming in Louisiana after Fred Kennedy was killed performing a riding stunt. The film was later completed in California.
Director John Ford suggested the scene with the boys' military academy, and according to the producers, he ad-libbed it.
Director John Ford's only feature film set during the Civil War, although he did direct a segment of How the West Was Won that was set during the Civil War.
The film is based on the true-life raid by Col. Benjamin Grierson who, as shown in the movie, began his expedition--known as Grierson's Raid--from LeGrange, Tennessee, in April of 1863.
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.
The producers originally wanted Clark Gable for the leading role.
The quote at the Greenbriar dinner, "And yet your fair discourse hath been as sweet as sugar making the hard way sweet and delectable" is from "Richard II", Act II Scene 3 by William Shakespeare.
When John Wayne (Col. Marlow) first meets William Holden (Maj. Kendall), he accuses him of being out of uniform because he is not wearing his sidearms. In that particular scene, Marlow is wearing a cavalry sword. But throughout the rest of the film, Marlow does not wear any sidearms. Even when the Confederate forces are charging through the street and one of his junior officers offers him a pistol, he waves it off.