The series was aimed at teenaged boys and young families. It was known for the breakthrough performances of the 12-year-old Kurt Russell in the title role and Charles Bronson as the second wagon master, Linc Murdock in the last thirteen episodes. Bronson began his role in the episode "The Day of the Toll Takers". Each episode begins with the title "The Day of..." Although it started out with an ensemble cast, which included Dan O'Herlihy in the role of Jaimie's father, Sardius "Doc" McPheeters, who often yields to alcohol and gambling, by the end of the run it had largely been reduced to the characters of Jaimie and Linc. Donna Anderson played Jenny, a young pioneer woman who befriends Jaimie during the perilous journey westward. Mark Allen was cast in nineteen episodes as Matt Kissel, with Meg Wyllie in eighteen segments as Mrs. Kissel. In nine episodes, real-life child barbershop quartetThe Osmond Brothers portrayed the singing sons of the Kissel family, all with given names of books of the Old Testament, Alan Osmond as Micah Kissel, Merrill Osmond as Deuteronomy Kissel, Jay Osmond as Lamentations Kissel, and Wayne Osmond as Leviticus Kissel. Michael Witney in fourteen episodes portrayed the first wagon master, Buck Coulter, with his last appearance in "The Day of the Pawnees, Part 2". Witney was replaced by Bronson in the next episode. Hedley Mattingly was cast eight times as Coe, and James Westerfield appeared seven times as John Murrel. Other recurring roles were filled by Sandy Kenyon in five episodes as Shep Baggott, stuntman Paul Baxley four times as Tracey, and Mike DeAnda in five assorted roles. Vernett Allen, III, was cast as Othello in nine episodes. Guthrie Thomas, the now veteran singer-songwriter, was also included in the cast of character actors as a "double" for Kurt Russell when horses were involved. Thomas and Russell were only months apart in age and the T.V. producers did not want Russell harmed because of insurance liabilities. Thomas had been raised on several ranches, one of which was owned by the film actor, Francis Lederer, and fulfilled the age and horse riding requirements of Russell's role as Jaimie McPheeters. Thomas was accustomed to the film business as several motion pictures, one being John Ford's Sergeant Rutledge, had been filmed at Lederer's Mission Stables, now an historical California landmark. Veteran western actor Slim Pickens, a close friend of Thomas' family, was responsible for his getting a screen test and subsequent roles.
After the series was canceled, Kurt Russell and Charles Bronson reprised their roles of Jaimie McPheeters and Linc Murdock in the 1964 theatrical movie called Guns of Diablo, an expanded color version of the series' final episode, "The Day of the Reckoning". Russ Conway appeared in the film as "Doc" McPheeters, replacing Dan O'Herlihy in new sequences.
