Snapshot: You've just finished reading the script for a commercial, training video, or movie, and consulted with the director. Now, it's your job to come up with the actors—including those 50 beefy oarsmen extras. You then schedule an audition for the actors and, along with the director, run the audition. To maintain a fresh stable of talent, you're continuously talking to actor's agents, seeing plays, gaining insight from drama department chairs, trolling actor databases, and perhaps offering seminars on how to land acting roles. To become a casting director, you need an eye for quickly telling whether or not an actor is right for the part. A good visual memory will help you remember which actors to invite to the audition. And patience is key. It often takes a long time to find the right person. Finally, at auditions, you're in charge of getting actors to relax so they can present their best self.
Getting there: The best way to start is as an intern or casting assistant at a casting agency or acting agency, notably William Morris, CAA, ICM, or Endeavor.
Learn more: Casting Society of America