In order to have a speaking role on a TV show, you most likely have to be a member of SAG (Screen Actors Guild) or AFTRA (Association of Film, Television and Radio Artists). Before you can become a member of a union, you have to have your work permit. Every state is different with the permits required for a teenager to work on a set. Be sure to check with your state's Department of Labor to find out what is necessary.
This varies from production to production, role to role. From the audition to the final casting process may take up to a month for each type of acting job for teens. Once the production is cast, the rehearsal period varies. It may be up to 3 months for a stage production, and less than a week for a commercial.
Make sure you check with the production company to find out what papers are required. Some theatrical productions may even require that the teen pays the theater in order to be in the production. Headshots and resumes are usually required for the audition process. Parents must be aware that they may have to spend several hundred dollars before their teen actually lands an acting job.
A teen acting job can be identified by the casting call that reads something to the effect of "Actor must be under the age of 18" or specifies that the teen must be the actual age of the character. If the casting call reads "18 to look younger," it means that the production company is looking to cast someone at least 18 years old to play a younger character.
The biggest misconception about teen acting jobs is that they come easily. They don't. The teen usually needs an acting coach, manager, agent or, at the very least, a willing parent to bring them to and from auditions. The production company utilizes a casting director, director, screen test, cold read process, matching process and more.
Many actors started out their acting careers as teenagers. Hunter Gomez, Sophie Oda, the Sprous Twins, Ryan Malgarini, Ralph Macchio, Scott Baio and many more successful actors had successful acting careers as teens. Many of them continue acting today, while others have gone on to become successful producers and directors.