(written from a Production point of view)
Kenneth Lavelle "K.L." Smith (26 October 1922 – 24 August 1981; age 58) is the actor who played a Klingon Captain in TOS: "Elaan of Troyius". He filmed his scenes on Friday 31 May 1968 at Desilu Stage 9.
Smith has made guest appearances on numerous television series, including Gunsmoke, Rawhide, The Untouchables, Wagon Train, Bonanza, The Virginian, and Gene Roddenberry's The Lieutenant.
He and fellow Star Trek actors Leonard Nimoy, Lawrence Dobkin, and William Schallert had uncredited appearances in the classic science fiction film Them!. Smith's other feature film credits include The Wild One (1953), Pushover (1954), Oh... Rosalinda! (1955, with Jill Ireland), and the Elvis Presley movies Jailhouse Rock (1957) and Roustabout (1964, with Teri Garr).