What does it mean to be a 'first actor'?

Question

I've noticed movies and tv shows say this in their credits. It says something like "with first actor blah blah blah"

Answer 1

When a new manuscript play is first produced, especially off-Broadway and on Broadway, the actors who play the roles are often given credit because they may have input to the process of refining the roles - the script may have been rewritten to suit their personal features. It is also considered to be more difficult to act in a script still being revised and never before performed and thus a prime credit.