In a French interview, Clint Eastwood) said of this movie, "It was an old-fashioned theme, probably too old fashioned since the film didn't do as well as we hoped. But if, as a film director, I ever wanted to say something, you'll find it in Bronco Billy".
This was Clint Eastwood's first film since Kelly's Heroes (1970) not to be produced by The Malpaso Company. At the time, divorce proceedings between Eastwood and Maggie Johnson were under way so the profits would have had to be shared with Maggie. Instead his Malpaso comrade Robert Daley set up Second Street Films to produce the movie.
In real life, Gilbert M. Anderson, nicknamed "Broncho Billy", has been attributed as being the first ever movie star of the Western film genre. "Broncho Billy" lived between March 21st 1880 and January 20th 1971. In the film industry, "Broncho Billy" was an actor, writer, producer, and director.
The make and model of the car that Bronco Billy drove was a 1957 Pontiac convertible according to publicity for the film though the IMCDb says that it is a 1960s Oldsmobile Super 88. Either way, the red painted vehicle is fitted with such chattels and fixtures as pistol door handles, bullhorns on the bonnet and fake upholstered cow-hide seat-covers.