After refusing Roddenberry's 1964 offer to play Spock, Kelley played Dr. Leonard "Bones" McCoy from 1966 to 1969 in '. He reprised the character in a voice-over role in ' (1973–74), and the first six "Star Trek" motion pictures (1979 to 1991). In 1987, he also had a cameo in "Encounter at Farpoint", the first episode of "", as Admiral Leonard McCoy, Starfleet Surgeon General Emeritus. Several aspects of Kelley's background became part of McCoy's characterization, including his pronunciation of "nuclear" as "nucular".