Geronimo was the first movie Chuck made while he was starring in The Rifleman.  Chuck played the title role of Geronimo and the movie also starred Adam West, Ross Martin, Pat Conway, John Anderson, Denver Pyle, Armando Silvestre, Enid Jaynes and Kamala Devi.  It was produced by Levy & Gardner and directed by Arnold Laven. 

The movie told the story from the Indians' point of view of being confined to reservations and being treated like children rather than being given any dignity and respect.  Geronimo was tricked into surrendering with promises that were never kept.  He and a band of his followers escape the reservation and embark on a mission to get the U.S. Government to realize the injustices being perpetrated on the once proud Apache people.

The movie was filmed in Mexico and it was a tough shoot.  Chuck worked out extensively before the movie began, even taking Karate lessons to learn to move more quickly.  The bareback riding was also dangerous in the wild galloping scenes.  Besides doing his own stunts, Chuck did his own riding and was instrumental in picking out the horse he was riding in the movie. After searching for three weeks, they chose a black stallion called El Torero to be Geronimo's.  Chuck was proud that this movie showed the Apaches in a good light.  He received some criticism for being a blue-eyed Apache, but the brown contact lenses he at first was going to wear really hurt his eyes. According to the publicity for the movie, they did some research and discovered that there were a few blue-eyed Indians so they eliminated the brown contact lenses.  Even without the contact lenses, Chuck spent two hours a day in make-up to have the wig and hawk-like nose applied.

Chuck's athleticism was put to good use, too, as well as his baseball playing skills.  One scene called for Geronimo to throw a flaming torch into an ammunition dump during an Apache raid.  They had a special effects expert standing by, but he wasn't needed.  Chuck hit the dump with the first throw and the ammunition blew up as called for in the script.

They also incorporated into the movie an Apache rite, putting on the moccassins.  The Apaches had a special ceremony and prayers as they presented a baby with his first moccassins as he learned to walk.  That attention to detail was evident in every aspect of the movie.