Don Siegel, who had directed the pilot and several episodes of the TV series, directed the film. It was a story that centered around two villains, with a script that made the villains interesting and gave them some really sharp dialogue. In fact, the bad guys are so interesting that Siegel wanted to center the film on them. It was only at the studio's insistence that he made the characters from the TV show an important part of the story. Heck, Warner Anderson still ended up with third billing.
Richard Jaeckel also leaves a mark as an alcoholic thug hired to drive Dancer and Julian around San Francisco.