The Film Experience gets it right in calling Mercedes McCambridge “one of the most singular character actresses of the 1950s.” Her work in Johnny Guitar (1954) deserves a posthumous Oscar (let's start that as a thing, Nathaniel!) and she also shone in Giant (1956), among many other films and TV gigs.
Later on, she was just a hell of a lot of fun, but she also became an inextricable part of Linda Blair's performance in The Exorcist (1973) as the voice of that pesky demon, a job that has become the stuff of legend.
Check out The Film Experience's remembrance here.
Keep reading to listen to an incredible interview with McCambridge, who re-creates her demon voice using—what else?—her chronic bronchitis ...