The Ultimate Guide to Epic Star Trek Crossovers in the 1990s

During the 1990s, Star Trek experienced a golden age with the success of Star Trek: The Next Generation leading to the creation of two interconnected spinoff series. Star Trek: Deep Space Nine, which debuted in 1993, became the first of these spinoffs. Its premiere episode featured Patrick Stewart and introduced Colm Meaney's Chief O'Brien, following the tradition established by the premiere of TNG that included a cameo by DeForest Kelley as Dr. Leonard "Bones" McCoy. This gesture became a touching way of passing the torch to the next generation.

In 1995, Star Trek: Voyager premiered with its first mission launching from Deep Space Nine. As a result, characters from both shows had brief interactions. Although there were attempts at more ambitious crossovers, such as a season finale of Deep Space Nine that would see the USS Enterprise-D defending the station from invading Cardassians, these proved challenging to realize. Instead, the Trek shows of the 1990s opted for a series of smaller crossover episodes, presenting the Star Trek universe as a vast fictional world for the very first time.

21 DS9: Emissary (Jean-Luc Picard)

20 DS9: Past Prologue (Lursa & B’Etor)

In order to introduce a new era of Star Trek: The Next Generation, the presence of Captain Jean-Luc Picard (Patrick Stewart) in Star Trek: Deep Space Nine was indispensable. The dynamic interactions between Picard and Commander Benjamin Sisko (Avery Brooks) were soul-stirring and set the tone for the distinctiveness of DS9. Sisko faced challenges with Jean-Luc Picard, clearly showcasing that as Bajor's Emissary, his fidelity wouldn't always align with the Federation. This sharp contrast to Picard's unwavering commitment to the Prime Directive and the Federation's mission made his appearance the ideal opportunity to lay the foundation for the future of DS9.

In the following episode of DS9, the nefarious Duras sisters Lursa (Barbara March) and B'Etor (Gwyneth Walsh), who were well-known as villains in Star Trek: TNG, made an appearance. This appearance served to further emphasize the connections between the two shows. In "Past Prologue", the cunning Duras sisters attempted to manipulate the Bajoran terrorist Tahna Los (Jeffrey Nordling) and the Cardassians, pitting them against each other. They supplied Tahna with the potent substance called bilitrium, which he intended to use in a weapon capable of obliterating the wormhole. Unbeknownst to Tahna, the Duras sisters secretly shared information with Garak (Andrew J. Robinson), positioning themselves to profit from both sides of the Cardassian-Bajoran conflict.

19 DS9: Q-Less (Q and Vash)

18 DS9: The Forsaken, Fascination, and The Muse (Lwaxana Troi)

Sisko's encounter with Q was a defining moment that set him apart from Picard. While others had never considered physically confronting the mischievous deity, Commander Benjamin Sisko was the one who dared to do so. This daring act solidified in people's minds that Sisko was a distinct character, different from Picard. Moreover, it ensured that Q and Sisko would never engage in battle again. In the episode "Q-Less," the cosmic trickster paid a visit to DS9 with the intention of reuniting with Vash, Picard's former lover. However, Q's attempt to win her back failed, and Vash ended up partnering with Quark, the Ferengi businessman, leaving Q empty-handed.

Lwaxana Troi (Majel Barrett), mother of TNG's Counselor Deanna Troi (Marina Sirtis), appeared in three episodes of DS9. Being a Betazoid Ambassador, her first visit to the station was as part of a fact-finding mission in the Gamma Quadrant. Lwaxana developed an immediate attraction to Constable Odo (Rene Auberjonois), and their friendship remained strong throughout her time on DS9. Odo went as far as marrying Lwaxana Troi to protect her and her unborn child from separation. Additionally, Lwaxana played a pivotal role in helping Odo recognize his feelings for Major Kira Nerys (Nana Visitor), which he would eventually act upon in season 6 of DS9.

17 DS9: Multiple Episodes (Gowron)

16 DS9: Defiant (Thomas Riker)

Klingon Chancellor Gowron (portrayed by Robert O'Reilly) made frequent appearances in various episodes of DS9. He became more prominent starting from season 4 when the Dominion manipulated the Klingon Empire into declaring war against Cardassia. Throughout the series, the loyalty between Commander Worf (played by Michael Dorn) and Gowron was tested, ultimately leading to a ritualistic duel to the death in the final season of DS9. However, Gowron's first crossover appearance happened in a lighter episode during season 3 titled "The House of Quark," a Klingon wedding comedy. In this episode, Quark got involved in a scheme orchestrated by Klingon widow Grilka (played by Mary Kay Adams) to maintain control of her House following her husband's death. This scheme brought the Ferengi barman face to face with Gowron.

In season 3 of DS9, "Defiant" stood out as a notable crossover event, featuring the introduction of Jonathan Frakes as Commander William T. Riker. However, instead of reprising his role as Will, Frakes portrayed Riker's transporter clone known as Thomas. The episode unveiled Thomas Riker's defection to the Maquis and his bold act of stealing the USS Defiant to expose covert Cardassian military installations. Eventually, Thomas ended up in the custody of the Cardassians by the episode's conclusion. Although Jonathan Frakes and the DS9 writers' room had the intention to bring back the character in the future, the opportunity never materialized.

15 DS9: Sons of Mogh (Kurn)

Worf's brother Kurn (Tony Todd) appeared only once in the episode titled "Sons of Mogh". In this episode, Kurn implored Worf to kill him in order to restore their family's honor. The House of Mogh had fallen into disgrace because of Worf's opposition to the war with the Cardassians, and Kurn found it unbearable to live with the shame. Despite initially agreeing to perform the ritual, Worf's attempt was foiled by Odo and Lt. Jadzia Dax (Terry Farrell). Recognizing that assigning Kurn the role of a security officer on DS9 didn't resolve the underlying issue, Worf decided to have his brother undergo surgery to alter his appearance and erase his memories. This compelled Kurn to embrace a new persona as Rodek, leaving Worf even more isolated and lonely than before.

14 DS9: Sons And Daughters, You Are Cordially Invited (Alexander Rozhenko)

In Star Trek: DS9, two episodes feature Worf's son Alexander Rozhenko (played by Marc Worden), including his presence at Worf and Dax's wedding in "You Are Cordially Invited". Initially, Alexander resurfaces in the sixth season's "Sons and Daughters" as a surprised Worf discovers his son serving aboard the IKS Rotarran. Despite Alexander's clumsiness causing frustration and embarrassment for Worf, he eventually realizes the importance of allowing his son to find his own path. Following his participation in his father's wedding, Alexander transfers to the IKS Ya'Vang for the remainder of the Dominion War.

13 DS9: Doctor Bashir, I Presume? (Dr. Lewis Zimmerman)

When the time came to choose a model for the next generation of Emergency Medical Hologram, it was only natural that Dr. Julian Bashir was selected. Additionally, Dr. Lewis Zimmerman (portrayed by Robert Picardo), the brilliant mind behind Star Trek: Voyager's EMH, decided to pay a visit to Deep Space Nine. Zimmerman, although a genius in his own right, had a weakness for the finer things in life, such as beautiful women, gambling, and indulging in alcohol. This was quite the opposite of his creation, who had a more refined taste for pursuits such as opera and literature.

12 DS9: Through The Looking Glass (Mirror Tuvok)

Tim Russ, the only cast member from Star Trek: Voyager, had the unique opportunity to portray his alter ego in the Mirror Universe. Unlike their counterparts, Voyager never ventured into this alternate reality. Aired in April 1995, just three months after the start of Voyager, the episode titled "Through the Looking Glass" cleverly acknowledged the presence of Deep Space Nine, the newest addition to the Star Trek franchise. In this particular episode, Sisko was transported to the Mirror Universe, where he aimed to persuade Jennifer Sisko, played by Felecia M. Bell, to align herself with the Terran Rebellion. This group also included Mirror Tuvok.

11 VOY: Caretaker (Quark and Morn)

Unlike the events in DS9's "Emissary," the passing of the torch from Commander Benjamin Sisko to Captain Kathryn Janeway (Kate Mulgrew) did not occur in Star Trek: Voyager. However, as the USS Voyager set off from DS9 to venture into the Badlands in search of Tuvok and the missing Maquis, an incident unfolded. Ensign Harry Kim (Garrett Wang) found himself on the verge of being deceived by Ferengi bartender Quark, but fortunately, Lieutenant Tom Paris (Robert Duncan McNeill) intervened. Meanwhile, amidst the chaos, the ever-present Morn, Quark's Bar's esteemed patron, could be spotted indulging in his drink.

10 VOY: Multiple episodes (Reginald Barclay)

Star Trek: Voyager featured the recurring character Lt. Reginald Barclay (Dwight Schultz), an anxious holodeck expert from Star Trek: The Next Generation. Initially, Barclay appeared as part of a holographic delusion experienced by Voyager's EMH Doctor (Robert Picardo), who believed he was his creator, Lewis Zimmerman. As the series progressed, Barclay became fixated on assisting the USS Voyager in returning to the Alpha Quadrant. He played a crucial role in the Pathfinder project, which re-established communication between Voyager and Starfleet. Additionally, he aided Admiral Janeway from an alternate reality in her journey back to Voyager's past during the show's finale.

9 VOY: Death Wish (Will Riker)

In the Star Trek: Voyager episode "Death Wish", Commander William T. Riker found himself summoned as a witness in a trial concerning the right to choose death for a renegade Q entity known as Quinn (portrayed by Gerritt Graham). Initially angry at being entangled in another one of Q's schemes, Will later discovered that Quinn had actually saved the life of one of his own ancestors. This revelation highlighted the potential positive impact that even a Q contemplating suicide could still contribute to the universe. Unfortunately, despite this crucial information, Riker was unable to retain his memories of the trial. As a result, he was unable to inform Starfleet about Voyager's dire situation.

8 VOY: Multiple episodes (Q)

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While Picard will always hold a special place in his heart, Janeway was a close second during Star Trek: Voyager. Q was so captivated by Kathryn Janeway that he dared to suggest mating with the Starfleet Captain in order to restore harmony to the Q Continuum. The interaction between Q and Star Trek's first female Captain brought a refreshing shift in dynamics, further explored in his three appearances on Voyager. These episodes delved into the intricacies of life within the Q Continuum, thrusting the Voyager crew into the midst of the godlike race's civil war. Additionally, they introduced Q's son, Keegan de Lancie, adding an intriguing new element to the storyline.

7 VOY: Multiple episodes (Deanna Troi)

When Reg Barclay's obsession with USS Voyager became problematic, he sought assistance from Counselor Deanna Troi. Deanna made three notable appearances in Voyager, initially aiding Reg with his Voyager fixation. Subsequently, she acted as a mediator during a dispute between the Doctor and his creator, Lewis Zimmerman. In her final appearance on Voyager, which took place in the episode "Inside Man," Deanna played a crucial role in helping Reg expose a Ferengi scheme to profit from the Borg nanoprobes within the DNA of Seven of Nine (Jeri Ryan).

6 VOY: Timeless (Geordi La Forge)

In "Timeless", Ensign Harry Kim, Commander Chakotay, and the Doctor from the future attempted to alter history by saving Voyager from a disastrous crash. In order to fulfill their mission, they had to steal a Delta Flyer, which caught the attention of the USS Challenger. Interestingly, Captain Geordi La Forge, played by LeVar Burton (who also directed the episode), commanded the Challenger and found himself in a tense standoff with Chakotay. Both men recognized the sacrifices necessary to achieve their respective goals.

5 VOY: Multiple episodes (Borg Queen)

Predictably, due to being stranded in the Delta Quadrant, the USS Voyager frequently encountered confrontations with the Borg Collective. These encounters often resulted in the crew of Voyager coming face to face with the Borg Queen, a character that was initially introduced in Star Trek: First Contact. Throughout the course of Star Trek: Voyager, the Borg Queen featured in three separate two-part episodes: "Dark Frontier," "Unimatrix Zero," and "Endgame." Alice Krige, the original actress to portray the Borg Queen, only appeared in the final episode of Star Trek: Voyager, while Susanna Thompson took on the role in the earlier episodes.

4 TNG: Birthright, Part 1 (Julian Bashir)

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In the episode "Birthright" of Star Trek: The Next Generation, the USS Enterprise-D, commanded by Captain Jean-Luc Picard, returns to Deep Space Nine. Lt. Commanders Data and Geordi La Forge join forces with DS9's Dr. Julian Bashir to examine a mysterious device discovered in the Gamma Quadrant. Upon further investigation, it is discovered that this device grants Data the ability to have dreams. This concept of a dreaming android intrigues Dr. Bashir, who assists Data in unraveling the enigmatic visions, with the aim of documenting their findings in a captivating paper for the prestigious Starfleet Cybernetics Journal.

3 TNG: Firstborn (Quark)

2 Star Trek: First Contact (The Doctor)

Commander Will Riker reached out to Quark, the Ferengi bartender from DS9, in the episode "Firstborn" to gather intelligence on the infamous Duras sisters. Initially evasive, Quark's reluctance faded when Riker tempted him with a bribe - a bundle of vouchers for 12 bars of latinum. Little did Quark know, Riker had already rendered these vouchers null and void, making the whole transaction a sham. Although Quark was intended to make an appearance in the film Star Trek: Insurrection alongside the TNG cast, his scene was ultimately removed due to time constraints.

Although not technically the same EMH from Star Trek: Voyager, there is a notable crossover in Star Trek: First Contact. In a moment of distress, Dr. Beverly Crusher (played by Gates McFadden) activated the Emergency Medical Hologram (EMH) as a diversionary tactic while evacuating the sick bay aboard the USS Enterprise-E to escape from the Borg invasion. Additionally, Voyager's Ethan Phillips made an appearance in First Contact, but not as his character Neelix. Instead, he portrayed a nightclub owner in one of Captain Picard's Dixon Hill holonovels.