After a handful of non-formula westerns, Charles Starrett returned to the mixture as before in Thundering Frontier. Starrett plays Jim Fillmore, kind to old ladies, small animals and heroine Norma Belknap. In contrast, the villains are kind to no one, least of all struggling building contractor Square Deal Scottie, whose projects are continually targeted for demolition and his payroll is forever being stolen at gunpoint. A good 25 percent of the film's running time is given over to Bob Nolan and the Sons of the Pioneers, whose C&W croonings are pleasant but a bit much.
| Actor | Role |
|---|---|
 Charles StarrettJim Filmore | Jim Filmore |
 Iris MeredithNorma Belknap | Norma Belknap |
 Ray BennettEd Filmore | Ed Filmore |
 Alex CallamSquare Deal Scottie | Square Deal Scottie |
 Carl StockdaleAndrew Belknap | Andrew Belknap |
 Fred BurnsHank Loomis | Hank Loomis |
 Bob NolanBob | Bob |
 John TyrrellBartender Mac | Bartender Mac |
| FFrancis WalkerHenchman Stub | Henchman Stub |
 John DilsonCarter Filmore | Carter Filmore |
 Pat BradyMusician (uncredited) | Musician (uncredited) |
 George ChesebroHenchman Dirk (uncredited) | Henchman Dirk (uncredited) |
 Hugh FarrMusician (uncredited) | Musician (uncredited) |
| KKarl FarrMusician (uncredited) | Musician (uncredited) |
 Ray JonesHenchman (uncredited) | Henchman (uncredited) |
 Eddie LaughtonClem (uncredited) | Clem (uncredited) |
 Lloyd PerrymanMusician (uncredited) | Musician (uncredited) |
| TTim SpencerMusician (uncredited) | Musician (uncredited) |
 Blackie WhitefordHenchman (uncredited) | Henchman (uncredited) |