It is a known fact that Trejo had several problems with the authorities during his youth and that he has been in prison more than a few times. However, a lesser known fact is that during his time in San Quentin prison, Trejo developed one of his passions: boxing. While competing, he also helped young people overcome their addiction problems and thanks to this combination of the 2, he made it to the big screen. One of the boys he helped, got him to meet on the set of Runaway Train with screenwriter Edward Bunker, who remembered his talent as a boxer and offered him a position training his actors. It was during that job that the director decided to give him a supporting role in the film.