Directed and produced by William A. Wellman, the screenplay was adapted by Robert Carson, based on the 1924 novel of the same title by P. C. Wren. The music score was by Alfred Newman and cinematography was by Theodor Sparkuhl and Archie Stout.
The film is a virtual scene-for-scene remake of the 1926 silent version of the same title starring Ronald Colman. This is probably the best known adaptation.
The film opens up with a company of French Foreign Legionaries approaching a desert fort in the Sahara. From a distance the fort appears occupied with flag flying, but upon closer inspection the garrison consists of dead men propped up behind the parapets. However a single shot is fired from inside and an officer and a bugler from the relief column climb the outer wall to investigate. They separate and the bugler goes missing. The officer finds two bodies that are not staged like the rest and a note on one admitting to the stealing of a valuable sapphire called the "Blue Water". After the officer leaves the fort to rejoin his legionaries waiting outside, fire suddenly spreads through the building.
Fifteen years earlier, Lady Brandon (Heather Thatcher), wife of absent spendthrift Sir Hector Brandon, and the three adopted Geste brothers, "Beau" (Gary Cooper), Digby (Robert Preston) and John (Ray Milland), her ward Isobel Rivers (Susan Hayward), and estate heir Augustus Brandon are introduced. Almost fifteen years pass showing them as young adults. They learn that Sir Hector Brandon intends to sell the "Blue Water," leaving nothing left for the estate, the children and Lady Brandon. At Beau's request, the gem is brought out for one last look when suddenly the lights go out and the jewel disappears. All present proclaim their innocence, but first Beau and then Digby depart without warning, each leaving a confession that he committed the robbery. John reluctantly parts from his beloved Isobel and goes after his brothers.
John discovers that they have joined the French Foreign Legion, so he travels to Paris and enlists as well. They are trained by the sadistic Sergeant Markoff (Brian Donlevy). Markoff finds out about the theft from his informant Rasinoff (J. Carrol Naish), who overhears joking remarks by the Geste brothers. Rasinoff convinces Markoff that Beau is hiding the gem.
Markoff arranges to divide the brothers. Beau and John are part of a detachment sent to man isolated Fort Zinderneuf. When the commander Lieutenant Martin dies from a fever, Markoff assumes command. Fearing the sergeant's now-unchecked brutality, legionnaire Schwartz (Albert Dekker) incites the other men to mutiny the next morning; only Beau, John, and Maris (Stanley Andrews) refuse to take part, out of loyalty to the Legion rather than to the hated Markoff. However, Markoff is tipped off by Voison (Harold Huber) and disarms the would-be mutineers while they are sleeping.
The next morning, Markoff orders Beau and John to execute the ringleaders, but they refuse. Before Markoff can do anything, the fort is attacked by Tuaregs. The initial assault is beaten off, but after each new attack, there are fewer defenders. Markoff props up the corpses at their posts to make it look as if there are still plenty of soldiers left. The final attack is repulsed, but Beau is shot, leaving Markoff and John the only men left standing.
Markoff sends John to get bread and wine. He searches Beau's body and finds a small pouch and two letters. When John sees what Markoff has done, he draws his bayonet, giving Markoff the excuse to shoot the only witness to his theft. However, Beau is not yet dead and manages to spoil Markoff's aim, allowing John to stab him. John and Beau hear a bugle announcing the arrival of reinforcements, Digby among them. Beau expires in his brother's arms after telling him to take one of the letters to Lady Brandon and leave the other, a confession of the robbery, in Markoff's hand. John escapes unseen by the relief column.
Digby volunteers to find out why there is no response from the fort. He discovers Beau's body and, remembering his oft-expressed wish, gives him a Viking funeral. He places Beau on a cot, with a "dog" (Markoff) at his feet, and sets fire to the barracks. Then he too deserts.
He finds John outside the fort. Later, two American friends (played by Broderick Crawford and Charles Barton) also desert, and together, they begin the long journey home. Desperate for water, they find an oasis, but it is occupied by a large band of tribesman. Digby tricks them into fleeing by sounding a bugle to signal a charge by non-existent Legionnaires, but he is killed by a parting shot.
John returns home. Lady Brandon reads Beau's letter, which reveals that Beau stole the gem because he knew it was a fake. Lady Brandon had sold the real one years before, and Beau wanted to protect her. As a child, he was hiding in a suit of armor and witnessed the transaction (which is shown in a flashback near the beginning of the film).Gary Cooper as Michael "Beau" Geste
Ray Milland as John Geste
Robert Preston as Digby Geste
Brian Donlevy as Sergeant Markoff
Susan Hayward as Isobel Rivers
J. Carrol Naish as Rasinoff
Albert Dekker as Schwartz
Broderick Crawford as Hank Miller
Charles Barton as Buddy McMonigal
James Stephenson as Major Henri de Beaujolais, commander of the relief column
Heather Thatcher as Lady Patricia Brandon
James Burke as Lieutenant Dufour
G. P. Huntley Jr. as Augustus Brandon
Harold Huber as Voisin
Donald O'Connor as Beau as a child
Billy Cook as John as a child
Martin Spellman as Digby as a child
Ann Gillis as Isobel as a child
David Holt as Augustus as a child, a despised playmate
Harvey Stephens as Lieutenant Martin
Stanley Andrews as Maris
Harry Woods as Renoir, a Legionnaire deserter
Arthur Aylesworth as Renault, another deserter
Henry Brandon as Renouf
Barry Macollum as Krenke
Ronald R. Rondell as Bugler
The film was banned in parts of Canada out of respect for the French government. It has a 100% approval rating on Rotten Tomatoes.
Brian Donlevy was nominated for the Academy Award for Best Supporting Actor for his role in the film.
According to the documentary The Making of a Legend: Gone with the Wind, the much-awaited Civil War spectacular was first shown, without prior knowledge of the audience (and without finished credits or music), in a small theater that was supposed to be showing Beau Geste.