He had memorable appearances as "Falseface" on the Batman TV series and provided the voice of "The Keeper" for "The Cage", the pilot episode of the "Star Trek" (1966) series. He turned down an offer to be a regular cast member on that show, rejecting the part of Dr. McCoy as he did not want to play third fiddle to William Shatner and Leonard Nimoy. Producer Gene Roddenberry, who had offered him the role of "Bones" McCoy, was not offended by Throne turning him down, and cast him as "Commodore Mendez" in the two-part episode "The Menagerie", which included most of the original pilot, although by then The Keeper's voice had been re-dubbed by another actor. He also later played "Senator Pardac" in the "Star Trek: The Next Generation" two-part episode "Unification," appearing with Leonard Nimoy, whose Mr. Spock was the role he had coveted a generation before.