In The Night of the Hunter, serial killer, Harry Powell's (Robert Mitchum) slightly-raised eyebrow is genius, the tiny movement revealing his heartlessness. To those who've seen the film, even still photos of Mitchum in character resend Powell's bone-chilling indifference to life.
Another fine example of communicative expression occurs in The Devil Wears Prada when Miranda Priestly (Meryl Streep) smugly and finalistically hummed, "Um-huh," not quite under her breath, making audiences frown. Streep's acting was brilliant: anything more or less alters the message.
What other actors in a particular role – as opposed to say, Bruce Willis' role-to-role, smart-assed half-smile – use a powerful, signature expression – including facial, verbal, or body language – to define a specific character? What does the expression communicate? Are there actors able to reproduce this mastery via different expressions for different roles? In which roles? With which expressions?
First I could think of is Al Pacino in The Godfather Part II. In most of his scenes he's silent, seated, listening to others speak or thinking by himself. Yet even if his actions don't vary much, his brooding face express so many emotions: anger, shock, pain, amusement, and even when he's worried. Still one of Pacino's best, and establishes Michael Corleone's taking over of their family business – Joie8 years ago