The Singing Outlaw was a 1938 B movie directed by Joseph H. Lewis starring Bob Baker as a singing cowboy.
A singing outlaw named Cueball and a U.S. Marshall kill each other in a shootout. A bystander played by Bob Baker decides to take over the Marshalls identity. To trap the local outlaw gang he pretends to be Cueball. He finds himself struggling to stop the cattle rustlers and win the love of the daughter of a rancher, played by Joan Barclay. Things get complicated when a Sheriff captures him with the gang, and he nearly gets hung before it is proved that he is not Cueball.A reviewer said The second of Bakers outings as a singing cowboy in notable for Millers exceptional camera work and Lewis emphatic direction. ........
Source: Wikipedia