DeForest Kelley Made A Change To Star Trek's Dr. McCoy In The Voyage Home

It's unlikely that any of the actors who appeared on "Star Trek" in 1966 would assume they would be playing the same roles 18 years later, but "Star Trek" has had a curious habit of longevity. Each time the franchise dies out, the landscape shifts and the series is revived. That's certainly what happened in 1979 with the release of "Star Trek: The Motion Picture" (which isn't boring, despite its reputation). After the original series was canceled in 1969, it was put into eternal syndication, allowing new audiences to find it for years thereafter. Trek conventions began in earnest in the mid-1970s, interest was renewed, and, lo, "Star Trek" returned. Sequel movies were put into production, and by 1986, the franchise released Leonard Nimoy's "Star Trek IV: The Voyage Home," the biggest hit in all of "Star Trek" until the release of J.J. Abrams' film in 2009. 

Also by 1986, the characters had aged from their mid-30s to their mid-50s, and the cast had to consider the long careers of Starfleet officers. They were clearly eager to keep serving together but were now sporting higher ranks and were perhaps even aging out of the space adventure game. If you ask me, "The Voyage Home" still should have ended with the heroes all being drummed out of Starfleet for their many transgressions. 

Back in 2014, StarTrek.com unearthed a 1986 audio interview with DeForest Kelley, who had played Dr. McCoy on and off for essentially two decades at that point. In the interview, the actor commented on the progress Dr. McCoy had made since the early days, and how large character developments had to be made from film to film, as opposed to the incremental character development he worked on during a weekly TV series. Notably, he said, Dr. McCoy had mellowed out a lot.

Kelley talked about the timeline of four feature films vs. the timeline of the 79 episodes of the original series, and how character arcs must be condensed for the latter. On a weekly show, a character isn't necessarily going to change in two weeks, but with a year or more between movies, new changes must be considered. Most notably, McCoy had to develop a new relationship with the Vulcan Spock (Nimoy). On the series, McCoy was openly annoyed by Spock's cold logic. After working with Spock for 20 years, though, that relationship had to evolve. Kelley said: 

"It's very difficult to expand or flesh a character out in a motion picture, so to speak. When we're doing them, it takes a couple of years to get one out. If we were still doing the series, why, it would be a lot of fun to see how these characters change during the aging process. So what I tried to do in ['The Voyage Home'] is kind of ... not soften McCoy, but he's become a little more attuned to Spock and he's looking at him more or less with a bit of amusement, as opposed to becoming so irritated with him."

This made sense, especially after the events of "Star Trek III: The Search for Spock." In that film, McCoy carried Spock's consciousness inside his brain so that it could be salvaged and placed back in an empty body late in the movie. He also committed a brazen act of mutiny, helping Kirk (William Shatner) and his other crewmates hijack the U.S.S. Enterprise for entirely selfish ends. The hijacking would eventually lead to the destruction of the Enterprise. After so much sacrifice, McCoy would necessarily have to be warmer and more peaceful about working with Spock.

Kelley also noted that a TV schedule allowed for more creative opportunities, specifically the opportunity to get things wrong every once in a while. When one is making 20-odd episodes a season and shooting on a tight, weekly schedule, there are bound to be stories that are a little rushed, and perhaps half-baked. Audiences would be forgiving, however, as there would be a new episode seven days later to "reset" any ill feelings. Kelley knew that a movie had to get everything right the first time, as they were released as major, infrequent events. He also continued elaborating on McCoy's relationship to Spock, saying: 

"Not that he doesn't become irritated with Spock, but McCoy has mellowed a little bit during this timeframe. As I say, if we were doing even six 90-minute shows a year we could expand on that, but when you shoot one motion picture every two years, it's rather a problem because it's very difficult to satisfy everyone. We only did 79 episodes, but during those episodes, there was bound to be one episode that perhaps everybody would like. You can't do that with a motion picture because there's going to be somebody who's not going to like something about it." 

Kelley went on to admit in the 1986 interview that he was a lazy actor, and that he would have been content with the "Star Trek" gig, even if it didn't lead to a prolonged film franchise. He, like several other Trek actors, didn't think the show would last very long and that a sci-fi series might even eat into some co-stars' professional credibility. "[W]hen I saw Leonard with his makeup with the ears," Kelley said. "I thought 'Well, he's had it.'"