Blake Snyder wrote in his iconic script writing manual Save The Cat that a script should be written so that any number of actors in Hollywood can play every part. He recounts the story of how he once wrote a wonderful script but gave up on it because the only actor who could have played the lead character was Tim Allen, meaning that if Tim Allen was not available, the script was toast.
Casting is a fickle thing. In the production of the original Star Wars: Episode IV, George Lucas’s first choice for the actor to play Han Solo was Christopher Walken. When he was not available, he tried Nick Nolte. Then he approached Al Pacino. Followed by Burt Reynolds, Richard Dreyfus, James Caan, Kurt Russel, Sylvester Stallone, James Woods, Chevy Chase, Bill Murray, and Steve Martin. He only settled on Harrison Ford, an unknown actor at the time, as a last resort. When Lucas was casting Raiders of the Lost Ark, the role of Indy Jones was offered to Tim Matheson, Peter Coyote, John Shea, and Tom Selleck. They almost settled on Selleck, but the other audition he entered, Magnum PI for CBS, was picked up. Due to scheduling conflicts, Selleck turned down the risky movie venture. (Because Raiders was filmed in Europe, far from Union regulations, and because the filming of Magnum PI was delayed for six months, it turned out that Selleck could have done both roles without conflict.) Less than six weeks before filming started, Lucas reluctantly gave the part to Harrison Ford.
Casting a movie is such a juggling act that if a script is tailored to a certain actor, it would be doomed to fail because nobody wants to take on a project with such narrow prospects from the start. Then again, a movie script, at least in Hollywood, is re-written at least half a dozen times by half a dozen re-writers before it is filmed. If a story that best suits one actor had been cast by another, somebody will tailor it to fit the actor. So it should not be a complete loss. Still, the likelihood of a success will be a lot smaller, especially at the stage of selling the script.
Writing a novel is very different. You can cast anyone you want in your imagination. The reader will cast whoever they like. If you are having trouble creating a character, you can cast, for example, Daffy Duck as one of your characters and nobody will be the wiser. Especially if you are writing a very different kind of story. A political thriller, say.
If you are writing a teen vampire story, but you got the personality of one character from Criminal Minds and another character from Batman and another one from Die Hard, nobody would know as long as you attach different names and different looks to them.
Somehow, that does not apply to scripts, according to Blake Snyder. The potential buyer of the script will always ask “Who will play this character?” and “Who is the intended audience?”
Admittedly, I know nothing about the movie business and Blake Snyder was legendary for selling his scripts, so he must know a lot more than me. But somehow, I don’t buy it. Ian Fleming wrote the James Bond series with David Niven in mind. That did not stop the producers from casting Sean Connery.
The other day, I was discussing a short story I was writing for the Screen Craft Short Story Contest with my son. Although I have been writing stories since long before he was born, he is much less an amateur than me. He teaches story writing. And he nailed it when he said “This story needs William Shatner.” I took his advice and introduced the character Shatner played in the movie Show Time. No doubt Shatner will be the actor best suited to play the part, but I am sure any number of Hollywood actors could imitate him. Introducing a character who so obviously resembles a specific actor might kill my chances for winning the contest, but it sure helps my story.