The supporting cast features Forrest Tucker, Christopher George, Ben Johnson, Glenn Corbett, Andrew Prine, Bruce Cabot, Patric Knowles, Richard Jaeckel, Lynda Day George, Pedro Armendariz Jr., John Agar, John Mitchum, Ray Teal, Christopher Mitchum and Hank Worden with Geoffrey Deuel and Pamela McMyler receiving "introducing" credits.

Bribed by Murphy, corrupt Sheriff Brady secretly hires Neemo and his group of banditos, who kill two of Chisum's men and steal a herd of horses.

They are assisted by Billy "The Kid" Bonney, a notorious killer who was recently hired and given a chance to reform by John Henry Tunstall, Chisum's philanthropic British neighbor.

During Sallie's welcome party, Murphy sends Jess Evans and his gang to rustle Chisum's cattle, which are being taken to the United States Army to feed the Native Americans on a nearby reservation.

Billy is nearly killed when Murphy has Evans attack the wagon train as it is returning to Lincoln; in response, Tunstall decides to go to Santa Fe to ask Governor Axtell to intervene in the land war.

Billy, wanting revenge for his friend and mentor, and skeptical that justice will be done in Lincoln, knocks out Garrett and kills Morton and Baker.

Murphy convinces Governor Axtell to fire Justice Wilson and appoint bounty hunter Dan Nodeen, who harbors an old grudge against Billy, as sheriff.

While a large posse scours the countryside to find Billy, he gathers his allies, starting with two of Tunstall's wranglers, Charlie Bowdre and Tom O'Folliard.

Murphy is impaled on a decorative bull's horn he was using as a weapon; Nodeen, his paymaster dead, leaves town, pursued by Billy.

He is appointed Sheriff of Lincoln County, and the next governor of the territory, Lew Wallace, declares amnesty for those involved in the land war.

[4][5][6] Michael Wayne, John's son and the film's executive producer, took on the project of making Chisum because he felt the story summed up his father's political views.

Fenady was sort of a scholar about the Lincoln County Cattle War, which was a conflict over water and cattle—trading cattle—and John Chisum actually became a very powerful landowner.