During Hollywood’s Golden age, most studios signed their actors to seven year contracts for a set weekly salary. If actors made themselves available to do whatever they were assigned, they would get their weekly check regardless of whether they actually worked that week. The studios would sign actors of various types- lead actors, character actors and supporting actors, all with different salaries as determined by studio management. Even within these types, there were A-Listers and B-Listers. An A-Lister would only get cast in A-List productions. B-Listers mostly got cast in B-List films, though they could often get supporting roles in A-List films.
Sometimes a studio might put a newly hired actor who they eventually saw as being an A-Lister into B-List productions to get them acquainted with the filmmaking process. These actors often took bit parts in the B-List films, many times hidden under wigs, so that when they were ready to jump onto the A-List, the studio’s PR machine could pretend they were newly discovered. This process made it easier to make films without costly delays. If an actor had to bow out of a project, the studio could quickly replace him with a call to the casting office instead of starting from scratch.
MGM and Louis B. Mayer perfected the system, optimizing it by making sure there was always a steady stream of talent available to feed its machine.
