(Image: "Devil's Due", Star Trek: The Next Generation)
We watch movies and television programs, so we see actors all of the time. But unless we work in the entertainment business, their craft remains a mystery. A good actor makes it look easy, but not everyone is a good actor.
What makes for a good actor? Marcus Geduld, a theater director, responded to that question on Quora, which was then re-posted on Slate. Geduld says that there are 5 qualities that denote the good actor:
First, for me, an actor is good if he makes me believe he's actually going through whatever his character is going through. I'm talking somewhat about physical stuff (“He really is getting shot!” “He really is jumping off a moving train!”) but mostly about psychological stuff (“He really is scared!” “He really is in love!”). If an actor seems to be faking it, he's not doing his job.
Second, the actor has to surprise me. This is the most nebulous requirement, but it's important. Except for really small parts that aren't supposed to call attention to themselves (e.g., a bank teller who just cashes the hero's checks), it's not enough for actors to just seem real. Seeming real is a requirement, but a second requirement is that I can't predict their every reaction before they have them.
One good demonstrations of the actor's craft that I encountered recently was this video by Patrick Stewart illustrating different ways to play the character of Shylock, my favorite character from Shakespeare. Stewart demonstrates different ways that an actor can express different meanings while using the same script.