Production notes

Before Robert Rossen was hired, Norman Corwin adapted Robert Penn Warren's novel All the King's Men into a screenplay. A Writers Guild arbitration board later awarded sole screenwriting credit to Rossen. Rossen's script makes several changes to the novel, including shifting the main story perspective from reporter Jack Burden, the novel's narrator, to Willie Stark himself. The film also removes any direct references to the state in which the film is set, as well as specificities of Southern American politics. Brian Neve, writing for Cinéaste, noted that this helps to "universalize" Stark's story.

Rossen originally offered the starring role to John Wayne, who found the script unpatriotic and indignantly refused the part. Broderick Crawford took the role and won the 1949 Academy Award for Best Actor, beating out Wayne, who was nominated for Sands of Iwo Jima. The casting of Crawford was considered risky, as he was not a leading man, nor a box office draw, but primarily a character actor. Columbia Pictures chief Harry Cohn favored Spencer Tracy, but Rossen rejected this, thinking the audience would find Tracy too likable. Rossen felt that Crawford's burly appearance and "tough guy" demeanor were well-suited to portray Stark as both everyman and demagogue. Crawford was so enthusiastic for the role that he took only half of his usual fee. To prepare, Crawford studied newsreel footage and voice recordings of Huey Long, though he noted the studio had an unspoken rule against mentioning the late Governor's death on set. John Derek had just made Knock on Any Door for Columbia. He and Crawford would be reunited in several more films.

The film was shot using local residents on location, rare in Hollywood at the time. The scene early in the film in which Stark is arrested for unauthorized public speaking was filmed at the old plaza in Suisun City, California, and the officer who warns and then arrests Stark was played by the local sheriff, A. C. Tillman. A house in nearby Fairfield was used as the exterior of Stark's house. Sets closely based on photos of the interior of that house were built in the nearby M & M Skateway (now gone) for the indoor scenes. The elementary school was a local one as well, but the building no longer exists. The San Joaquin County courthouse in Stockton, built in 1898 and demolished a decade after the film's release, was featured prominently. Don Siegel worked on the film as an uncredited second unit director.

Paul Tatara, writing for TCM, describes the film as "one of those pictures that was saved in the editing". Al Clark, the original editor, had difficulty making a coherent version from the large amount of footage that had been shot. Rossen and Columbia Studios head Harry Cohn hired Robert Parrish to make changes. However, Parrish's efforts proved unsuccessful as Rossen stayed heavily involved; after several weeks of editing, the film was still over four hours long. Cohn almost released this cut before Rossen told Parrish, "Select what you consider to be the center of each scene, put the film in the synch machine and wind down a hundred feet before and a hundred feet after, and chop it off, regardless of what's going on. Cut through dialogue, music, anything. Then, when you're finished, we'll run the picture and see what we've got." After All the King's Men won its Academy Award for Best Picture, Harry Cohn repeatedly gave Parrish credit for saving the film. Although Clark is credited as the film's editor and Parrish as editorial advisor, both of them were nominated for an Academy Award for Best Film Editing.

The film received wide acclaim upon its release. Film critic Bosley Crowther lauded the film and its direction in his review, writing, "Robert Rossen has written and directed, as well as personally produced, a rip-roaring film of the same title ... We have carefully used that descriptive as the tag for this new Columbia film because a quality of turbulence and vitality is the one that it most fully demonstrates ... In short, Mr. Rossen has assembled in this starkly unprettified film a piece of pictorial journalism that is remarkable for its brilliant parts." Critic William Brogdon, writing for Variety magazine, was also complimentary and praised Broderick Crawford's work, "As the rural Abe Lincoln, springing up from the soil to make himself a great man by using the opinionless, follow-the-leader instinct of the more common voter, Broderick Crawford does a standout performance. Given a meaty part, his histrionic bent wraps it up for a great personal success adding much to the many worthwhile aspects of the drama." It won an Associated Press poll in 1950 as the best film of 1949, and Broderick Crawford was regarded as the best actor in that same poll. On Rotten Tomatoes, All the King's Men holds a rating of 97% based on 70 reviews, with an average rating of 8.10/10. The website summarizes the consensus as: "Broderick Crawford is spellbinding as politician Willie Stark in director Robert Rossen's adaptation of the Robert Penn Warren novel about the corrosive effects of power on the human soul."

Film historian Spencer Selby calls the film "[A] hard-hitting noir adaptation of Warren's eloquent novel". Joe Goldberg, film historian and former story editor for Paramount Pictures, wrote about the content of the plot and its noirish fatalistic conclusion, "The plot makes sense, the dialogue is memorable, the story arises from the passions and ideas of the characters. It deals with graft, corruption, love, drink and betrayal, and the subversion of idealism by power, and it might even make someone angry... The story moves toward its conclusion with the dark inevitability of film noir." Author Harry Keyishian wonders if Willie Stark is "a good man corrupted by the political process, or a bad one whose inherent vice emerges when he gets a chance for power."

In 2001, the film was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant". The Academy Film Archive preserved All the King's Men in 2000. As of 2025 and beyond, it is notable for the last Best Picture winner to be based on a Pulitzer Prize-winning novel.

All the King's Men received seven Academy Awards nominations, winning three.