McCarthy died Saturday, said Cape Cod Hospital spokesman Dave Riley, who wouldn't reveal the cause of death or any other details.
McCarthy was a prolific actor whose career took off in 1938 with his Broadway debut in "Abe Lincoln in Illinois."
His most lasting fame would came from "Invasion of the Body Snatchers." In the 1956 film he vainly tried to warn residents in his small town of the evil pod people from outer space who were quietly taking over the personalities of everyone on Earth.
His frantic shouting of "You're next" to those in approaching cars became so well known among science fiction fans he was often asked to spoof the role. He more or less did that in the opening minutes of the 1978 remake, which starred Donald Sutherland as the hero menaced by the pod people.
"Body Snatchers" flopped at the box office, considered too bleak for audiences of the time. It was elevated to classic status, and its star to iconic status, after such critics as Francois Truffault hailed it and late-night television programmers embraced it.
McCarthy's other films included "A Gathering of Eagles," "The Best Man," "Mirage," "Hotel," "The Howling," "Twilight Zone - The Movie," "Inner Space," "Dark Tower," "Just Cause," "The Distinguished Gentleman" and "Steal Big, Steal Little."
He also appeared in one other classic film, although in a much smaller role. He was Marilyn Monroe's estranged husband in her last movie, 1961's "The Misfits."
He originally turned down the role when director John Huston approached him, complaining that it was too small.