It stars Joseph Cotten, Philip Carey and Darren McGavin.
The film begins at Board of Inquiry over the Battle of the Little Big Horn; specifically examining the conduct of Major Marcus Reno. Captain Bill Benton (perhaps inspired by Frederick Benteen) is called to the stand, and rather than merely answer questions from the board states that he will tell his version of the "true story" that the audience sees through flashback.
Benton relates his first arrival in the Wild West where his detachment is escorting the wife of the local Indian Agent Mr. Turner. The Indians attack the party and abduct Mrs Turner away from Benton's command. Benton's Army Scout "Dakota" advises against tracking the Indians until the next day due to their laying false trails that lead into ambushes. Dakota and Benton come across a wounded Indian who Dakota shoots so he will not have to starve on an Indian Reservation.
Received by his commanding officer Lt. Col. George Armstrong Custer, Benton is gently told his first encounter with the enemy has been disastrous but Custer confirms that he did the right thing by following Dakota's advice not to pursue the hostile party. Custer invites Benton to a dress dance held at the fort that evening and dismisses the distraught Mr. Turner by telling him that he will visit the hostile Indians who abducted his wife in the morning.
Benton's fiancee Caroline Reno is at the fort, but their relationship has grown cold due to Caroline's father Major Reno hating Benton. At the dress ball, where Custer wears a major general's tunic with Colonel's insignia, Major Reno comes in drunk and demands everyone address him as "Major General Reno" due to his former rank in the Confederate States of America's army and salute him. Custer replies with good nature attempting to reconcile the former warriors of the North and South but Reno is in a bad mood. He physically attacks Benton but only hits the floor prompting Benton to inform Caroline that her "family tree has fallen".
The next day Benton join's Custer's patrol who meet Crazy Horse and Sitting Bull to negoitiate Mrs. Turner's release. The Indians propose Custer release all his Indian prisoners in exchange for Mrs Turner. Custer decides on a compromise, he will hang the Indian leaders if Mrs Turner is not released. Mrs Turner is released.
Custer gains Benton's respect by Custer's disgust at the corrupt Indian Agents who he feels have been put in place by a corrupt Federal Administration that Custer and his wife Libby will confront in Washington. Before their departure the captive Indians unsuccessfully attempt to escape and are slaughtered.
In Washington, D.C., Colonel Custer destroys his military career by formally accusing many Federal politicians with corruption including Orvil Grant, the brother of the President of the United States Ulysses S. Grant. When the President refuses to meet with Custer, he begins to realise his military career may have come to a premature end.
Meanwhile, back in the West the Army's commander General Alfred Howe Terry visits the fort and summons Major Reno and Captain Benton to inform them that Custer is going to be court martialed. Major Reno is deflated when the General offers Captain Benton command of the 7th Cavalry and a promotion to Brevet Colonel. Captain Benton refuses and considers resigning his commission out of loyalty to his commander. Major Reno's daughter browbeats her father who says he will not accept command of the Regiment, gives his blessing to Caroline and Benton's marriage and gives up his drinking.
In Washington Senator James G. Blaine visits the humbled Custer and tempts him with an offer to be the party's candidate for President of the United States. The Senator informs Custer this can be accomplished through obtaining a reputation through his military exploits in a war with the Indians. The Senator assigns a newspaper journalist/minder possibly based on Mark Kellogg to Custer who is sent back without court martial to his Regiment.
Benton notices that Custer's empathetic feelings for the Native Americans have vanished and he is pushing his regiment into a war where he can claim glory. Custer motivates his command by personally shooting deserters in the back including his scout Dakota who has turned from Indian baiter to Indian booster. This prompts Benton to strike his commanding officer where he is arrested. He is freed by Indians who know of his attempts to help their people at the aborted escape but when his Indian friends are ambushed by a cavalry patrol Benton attempts to warn Colonel Custer of a mass Indian army made up of a combination of several tribes.
Darren McGavin ... Capt. Bill Benton
Joseph Cotten ... Maj. Marcus Reno
Philip Carey ... Lt. Col. George Armstrong Custer
Julie Sommars ... Caroline Reno
Nancy Kovack ... Elizabeth Bacon Custer
John Matthews ... Dakota
Michael Pate ... Sitting Bull
Don Haggerty ... Sen. James G. Blaine
Frank Ferguson ... Gen. Alfred Howe Terry
Stacy Harris ... Mr. Turner, Indian Agent
Iron Eyes Cody ... Crazy Horse
House Peters Jr. ... Reporter
John Napier ... Captain Thomas Custer
Boyd Morgan ... Telegrapher
Louise Serpa ... Mrs Turner
The Great Sioux Massacre was one of a series of films released by Columbia Pictures in the early to mid-1960s that were built around the reuse of large-scale action footage from other films, such as Nathan Juran's Siege of the Saxons and East of Sudan and John Gilling's The Brigand of Kandahar. Filmed near Old Tucson, Arizona, the action scenes of the actors in flat desert do not coincide with the hilly wooded Mexican landscapes of Salkow's Sitting Bull.
The screenplay by Salkow and Marvin Gluck was credited as "Fred C. Dobbs", the name of Humphrey Bogart's character in The Treasure of the Sierra Madre and then the name of a nightclub on Sunset Strip. Italian American and faux Native American actor Iron Eyes Cody, who also played Crazy Horse in Salkow's Sitting Bull, had appeared in the 1936 Custer's Last Stand. Iron Eyes also acted as technical adviser on the film. Louise Serpa, who played Mrs Turner, was a renowned rodeo photographer.