alt Hacker NewsActor and Director and Producer would be more than enough for everybody. Especially combined with several Oscar wins as director and producer, and even Oscar nominations as actor (on top of iconic roles).
But he has also been an OST composer for some films.
The point is a Homer or Twain, etc, were original authors of works and Eastwood was not an author of any of those works. If an unknown actor portrayed the lead in a Huckleberry Finn film, that would not elevate that actor to the level of a Mark Twain as an author.