Leonard McCoy - Development

Development

Star Trek creator Gene Roddenberry had worked with Kelley on previous television pilots, and Kelley was Roddenberry's first choice to play the doctor aboard the USS Enterprise. However, for the rejected pilot "The Cage" (1964), Roddenberry went with director Robert Butler's choice of John Hoyt to play Dr. Philip Boyce. For the second pilot, "Where No Man Has Gone Before" (1966), Roddenberry accepted director James Goldstone's decision to have Paul Fix play Dr. Mark Piper. Although Roddenberry wanted Kelley to play the character of ship's doctor, he didn't put Kelley's name forward to NBC; the network never "rejected" the actor as Roddenberry sometimes suggested.

Kelley's first broadcast appearance as Doctor Leonard McCoy was in "The Man Trap" (1966). Despite his character's prominence, Kelley's contract granted him only a "featuring" credit; it was not until the second season that he was given "starring" credit, at the urging of producer Robert Justman. Kelley was apprehensive about Star Trek's future, telling Roddenberry that the show was "going to be the biggest hit or the biggest miss God ever made". Kelley portrayed McCoy throughout the original Star Trek series and voiced the character in the animated Star Trek.

Kelley, who in his youth wanted to become a doctor, in part drew upon his real-life experiences in creating McCoy: a doctor's "matter-of-fact" delivery of news of Kelley's mother's terminal cancer was the "abrasive sand" Kelley used in creating McCoy's demeanor. Star Trek writer D. C. Fontana said that while Roddenberry created the series, Kelley essentially created McCoy; everything done with the character was done with Kelley's input.

"Exquisite chemistry" among Kelley, William Shatner, and Leonard Nimoy manifested itself in their performances as McCoy, Captain James T. Kirk and science officer Spock, respectively. Nichelle Nichols, who played Uhura, referred to Kelley as her "sassy gentleman friend"; the friendship between the African-American Nichols and Southern Kelley was a real-life demonstration of the message Roddenberry hoped to convey through Star Trek.

For the 2009 film Star Trek, writers Roberto Orci and Alex Kurtzman saw McCoy as an "arbiter" in Kirk and Spock's relationship. While Spock represented "extreme logic, extreme science" and Kirk symbolized "extreme emotion and intuition", McCoy's role as "a very colorful doctor, essentially a very humanistic scientist" represented the "two extremes that often served as the glue that held the trio together." They chose to reveal McCoy befriended Kirk first, explaining the "bias" in their friendship and why he would often be a "little dismissive" of Spock. Urban said the script was "very faithful" to the original character, including the "great compassion for humanity and that sense of irascibility" with which Kelley imbued the character. Urban trained with a dialect coach to create McCoy's accent. Urban will be reprising the role in Star Trek Into Darkness.