Every Star Trek show is an ensemble focusing on the lives of the crew of whichever starship or space station is the primary location. Sadly, these ensembles don't always endure as actors decide to leave to pursue other roles, or in some cases are even forced out. Given the grueling schedule of delivering over 20 episodes of a Star Trek show during the 1990s, it's hardly surprising that some actors lost their ion for the franchise, especially if they found their scripts lacking.
At the time of Commander Will Riker (Jonathan Frakes). It's unclear how true those rumors actually were, or whether they were a means to promote what became a turning point for TNG's popular appeal. Whatever the truth of Patrick Stewart's desire to leave Star Trek behind at the time, there are several other major characters before and after Picard who were written out when the actors portraying them decided to leave the franchise.
7 Jeffrey Hunter
The Starship Enterprise's Original Captain, Christopher Pike (Jeffrey Hunter), would never have existed had it not been for some quick thinking on the part of the Star Trek: The Original Series' production team. Hunter played Pike in Star Trek's first pilot, "The Cage", which was rejected by NBC for being "too cerebral." Although the network gave creator Gene Roddenberry and Star Trek a second chance, Hunter had decided not to continue in the leading role, eventually being replaced by William Shatner as Captain James T. Kirk.
However, despite this, Hunter's performance was eventually seen when scenes from "The Cage" were re-purposed for the two-parter "The Menagerie" as a time-saving measure when production on Star Trek season 1 fell behind. This established Pike as an earlier Enterprise captain and would eventually lead to Captain Pike getting his own show 56 years later in the form of Star Trek: Strange New Worlds. So while Hunter left before the franchise even started, his legacy lives on through Anson Mount's portrayal of the character.
6 Denise Crosby
Another actor who decided that Star Trek wasn't for them early in the process was TNG's Denise Crosby, who was dissatisfied with the writing of her character Lieutenant Tasha Yar. Despite being cast as the Enterprise-D's Chief of Security, Crosby felt that Tasha was often reduced to playing a background character. Denise opted to exit the series, and TNG creator Gene Roddenberry decided that the best way to write her out would be to shock audiences by killing her off in TNG season 1, episode 23, "Skin of Evil".
Despite leaving The Next Generation, Crosby would later return as Tasha in both an alternate timeline and in flashback. She would also play the villain role of Sela, Tasha's half-Romulan daughter, in several TNG episodes. The character of Sela was actually Crosby's idea, and was then worked on by the TNG writer's room. She was an excellent foil for Jean-Luc Picard and finally gave Denise Crosby a more substantial character that actually made an impact on TNG.
5 Wil Wheaton
While Star Trek fans staged a letter-writing campaign to reinstate Beverly Crusher actress Gates McFadden after her TNG season 2 firing, there was less love for Beverly's son Wesley (Wil Wheaton). Prior to being cast in TNG, Wheaton had been one of the leads in the movie Stand by Me, but his Star Trek commitments hampered the actor's attempts to build on his Hollywood successes. When Wheaton was cast in the movie Valmont, he requested time off, which was denied to him, because the episode he had to miss was important for the Wesley character. After turning the movie down, Wheaton realized that the episode in question had been rewritten to remove Wesley, something the actor saw as a punishment.
This poor relationship with the production staff led to Wheaton quitting TNG to pursue other acting roles. Like Tasha Yar, the young Crusher returned to TNG as a troubled Starfleet Cadet before Wesley eventually ed the Travelers. Wheaton has continued to maintain a close relationship with the franchise since, hosting the post-episode discussion show, The Ready Room, which airs after episodes of modern Trek shows, proving that few actors truly leave Star Trek.
4 Michelle Forbes
Michelle Forbes also left TNG to pursue a career in feature films, although her departure was slightly more complicated than that of Wi Wheaton's. Forbes ed TNG as Ensign Ro Laren in season 5, setting up the Cardassian occupation of Bajor, which would play a major role in the spinoff series transfer Ro to DS9, which apparently soured her working relationship with the TNG production team and almost meant she didn't get a proper send-off.
Thankfully, TNG season 7 was running behind on episodes and so the abandoned script "Preemptive Strike," which saw Ro betray Starfleet to the Maquis, was resurrected. It gave Michelle Forbes one of the most memorable character exits in all of Star Trek. Forbes' decision not to star in DS9 certainly didn't harm her career, as she went on to have roles in big shows like 24, Battlestar Galactica, and True Blood.
3 Terry Farrell
Terry Farrell was another actor who appeared to fall afoul of particular of the Star Trek production team. With Farrell's contract up for renewal ahead at the end of DS9 season 6, her character Jadzia Dax was replaced in season 7. Unlike Gates McFadden, Farrell wasn't fired, but has spoken in the ensuing years about how she was forced into leaving the show at the end of her contract. Exhausted from the grueling production schedule, Farrell requested a smaller role in the final season of DS9, something which was refused by producer Rick Berman and the executives at Paramount.
In the retrospective documentary What We Left Behind, Farrell says she feels that she was being bullied into accepting a full season 7, something that Berman denies. DS9 showrunner Ira Steven Behr was unaware of these negotiations, and was furious at having to kill off Dax when talks broke down and Farrell didn't renew her contract. Farrell went on to star in the Ted Danson sitcom, Becker, which strangely enough was produced by the same Paramount executives who had refused to give her a smaller role in DS9.
2 Geneviève Bujold
Despite becoming one of the best-ever Star Trek Captains, Kate Mulgrew was not the first choice for the role of Captain Janeway in Star Trek: Discovery's Doctor Kovich, David Cronenberg. The United Paramount Network was excited about the prestige that Bujold's involvement would bring, and Robert Beltran told Trek Movie in 2017 that she was one of the reasons he signed on for the role of her second-in-command, Commander Chakotay.
However, after completing only a day and a half of filming, Bujold left Voyager. The reason given that she was unprepared for the hectic schedule of working in network television. It has also been suggested that Rick Berman was unhappy with the quality of Bujold's performance as Janeway and that Bujold wasn't happy with the character as written. After Bujold's departure, Kate Mulgrew, who was no stranger to television production, was cast as Voyager's Captain Kathryn Janeway, and the rest is history.
1 Jennifer Lien
Alongside Neelix (Ethan Phillips), Kes (Jennifer Lien) was one of the Delta Quadrant natives that ed the crew of the USS Voyager. As an Ocampan, Kes had a limited lifespan of nine years, but Lien's time on Voyager was even shorter than that. On the instruction of UPN, who believed that there were too many characters in Star Trek: Voyager, Kes was written out in season 4 after the introduction of fan-favorite character Seven of Nine (Jeri Ryan). According to the book Star Trek Voyager: A Celebration, Jennifer Lien was experiencing issues in her personal life but could not, or would not, open up to the production team.
Although Lien's personal issues have garnered headlines in the years that followed her departure, there's nothing to suggest that they played a role in her departure. In truth, after Seven ed Voyager, there was no room for Kes. The character had reached a creative dead-end, and the writers had nowhere else to take her, and so she left the USS Voyager in season 4, episode 2, "The GIft", when her telekinetic powers put everyone at risk. Lien didn't stay away for long and would return as a vengeful and destructive Kes in the season 6 episode "Fury", proving once again that very few actors truly leave Star Trek.