Following the surrender of Geronimo, Massai, the last Apache warrior is captured and scheduled for transportation to a Florida reservation. On the way he manages to escape and heads for his homeland to win back his girl and settle down to grow crops. His pursuers have other ideas though.
On the outskirts of town, the hard-nosed Vienna owns a saloon frequented by the undesirables of the region, including Dancin' Kid and his gang. Another patron of Vienna's establishment is Johnny Guitar, a former gunslinger and her lover. When a heist is pulled in town that results in a man's death, Emma Small, Vienna's rival, rallies the townsfolk to take revenge on Vienna's saloon – even without proof of her wrongdoing.
Joe Branch, reputed to be the son of Jesse James, comes riding into Coffeyville Kansas, looking for proof one way or the other regarding the question of who his father was.
Brady Sutton returns from three years in prison and tries to go straight. One a member of the Butch Cassidy gang, he is still suspected of being cahoots with them. When Cassidy and his men rob the bank, he is blamed. Escaping from the townspeople, he once again joins up with Cassidy to wait for a chance to help bring him in.
A spirited cast kicks up its heels in a lively musical spoof of cowboy films crammed with spur-jangling tunes by Jay Livingstone and Ray Evans and decked out with colorfully stylized, Oscar.-nominated sets. Rosemary Clooney heads up the high-kicking, red-gartered girls of the Red Dog Saloon. They can-can. but she won't-won't unless Jason (Jack Carson) asks her to get hitched. Guy Mitchell and Gene Barry are gun-totin' polecats who think they've got a feud to settle. And Frank Faylen and Buddy Ebsen are among the folks who hope the gunslingers get itchy fingered - so they can hold a town barbecue during the funeral!
Sharpshooter Calamity Jane takes it upon herself to recruit a famous actress and bring her back to the local saloon, but jealousy soon gets in the way.
Ex-Pony Express rider Autry ties to protect his US mail franchise as the Pony Express gives way to stage coach mail and the telegraph. Gene's last film appearance as a singing cowboy.
After a stagecoach holdup, Frank Slayton's notorious gang leave Ben Warren for dead and head off with his fiancée. Warren follows, and although none of the townspeople he comes across are prepared to help, he recruits two others who have sworn revenge on the ruthless Slayton.
Wildcatter Jeff Dawson does his best to bring in a gusher in Mexico despite continual bandit raids. He asks for help from his ex-employer Ward Conway, but Conway, now married to Dawson's ex-lover Marina refuses, fearing that his wife will want to renew her romance with the other man.
Wes Anderson (Fred MacMurray) is caught cattle rustling and promptly jailed. The public is outraged, but, since Wes always worked at night, they don't know what he looks like. Still, they break into the prison and lynch a hobo they think is Wes, while the actual culprit sneaks off to see his old flame, Rela (Barbara Stanwyck), who has recently taken up with his straitlaced brother, Tom (William Ching). But Tom is envious of his outlaw brother, and he decides to join Wes in a life of crime.