The story of Billy Midnight is based on the historical character Robert Ford:
Robert and Charlie Ford were members of the Jesse James Gang, and the individuals who killed the infamous train robber, Jesse James, Robert Ford shot him in the head from behind while he was cleaning a painting. After that, he notified the authorities of his exploit, hoping to receive the $10,000 reward. The Fords went to various theaters reenacting, according to Bob, his "heroic deed". He made many enemies and received death threats. Bob Ford died on June 8th, 1892, after being shot by Edward O'Kelley in his own saloon.
Billy Midnight (Wilhelm Schnell) worked for many years with the gunslinger, Rabbit Matthews, he was the stable boy in the gang. Midnight knew Matthews personally. One night, Billy Midnight shot him in his sleep (it is not known why). He became an overnight celebrity and went to several theaters in St. Louis, San Francisco, and even St. Denis, reenacting Rabbit Matthews' assassination. His life as a popular celebrity didn't last for long, Billy Midnight received many death threats because people discovered the truth of his cowardly murder, this made Midnight extremely paranoid and he was always nervous and drinking. Died in the State of Lemoyne, on 1899.