A veteran of television and film westerns, he has portrayed two different participants in the legendary 1881 OK Corral gunfight between the Earps and the Clantons. In 1955, he played Ike Clanton in an episode of the TV series "You Are There" (1953), and in 1957, he played Morgan Earp in the film Gunfight at the O.K. Corral (1957). On "Star Trek" (1966), the USS Enterprise away team beam onto a planet and he again finds himself at the OK Corral, playing Tom McLaury.
Before landing the role of Dr. McCoy, he was offered the choice to play Mr. Spock. Years later, he played both for Star Trek III: The Search for Spock (1984).
Graduated from Decatur High School in Decatur, Georgia when he was only 16 years old.
Had a great love of poetry, both reading and writing it. Later in life, he used to charm Star Trek convention audiences with three poems about Gene Roddenberry ("The Great Bird of the Galaxy") and the Star Trek franchise. They were called "The Big Bird's Dream," "The Dream Goes On," and "The Dream Forever.".
He had originally wanted to be a Doctor.
He plays a medic in The Man in the Gray Flannel Suit (1956). Foreshadowing things to come, his character says, "This man is dead, Captain".
He told close friends that he always felt more comfortable in westerns then he did in science fiction.
He was cremated and his ashes scattered in the Pacific Ocean.
He was the most well-liked of the Star Trek cast and the only one that no one had a feud with at any point.
His personal favorite episode of "Star Trek" (1966) was "The Empath".
Inspired many fans to take up medicine. He and his wife visited one of them after graduating from medical school, after receiving an invitation.
Is one of only 32 actors or actresses to have starred in both the original "Star Trek" (1966) up to and including Star Trek VI: The Undiscovered Country (1991) and then in one of the spin-offs.
Made both his first (Episode "The Corbomite Manoeuvre") and last (Star Trek VI: The Undiscovered Country (1991)) Star Trek appearances with Nichelle Nichols.
Of the four main "Star Trek" (1966) cast members (the others being William Shatner, Leonard Nimoy and James Doohan), he is the only one who never appeared in "The Man from U.N.C.L.E." (1964), "Twilight Zone" (1959) or "The Outer Limits" (1963).
Often mistakenly billed as Kelly de Forrest.
Reportedly disliked doing the animated "Star Trek" (1973) series because he was never recording his lines at the same time as William Shatner and Leonard Nimoy. Kelley did not like this because he never got to interact with them and develop any rapport, which made reading his lines all the more difficult.
Shortly after Mr. Kelley's passing, "He's dead, Jim" was forever memorialized by being added in tribute to Dr. McCoy for two 1999 video games: StarCraft Expansion Set: Brood War (1998) (VG) and Shatner-oids, a spoof of the classic Atari game "Asteroids".
Shortly before his death, he won the "Golden Cowboy Boot" award, honoring his earlier work in westerns.
The "Star Trek: Enterprise" (2001) character, Admiral Maxwell Forrest played by Vaughn Armstrong, is named after him.
The oldest cast member of Star Trek.