As the crew of the USS Enterprise-D explored the galaxy on Star Trek: The Next Generation, they encountered some incredible characters who only appeared once. Led by Patrick Stewart's Captain Jean-Luc Picard, the characters of TNG have become one of the most beloved science fiction casts of all time. As they went on new adventures each week, Captain Picard and his crew made even the weakest episodes of TNG worth watching. However, some of TNG's best episodes became classics because of their guest stars.
With its episodic style of storytelling, Star Trek: The Next Generation introduced new characters each week who created the conflict for that week's plotline. Many of these characters only appeared in one episode, but left a mark on the franchise thanks in large part to the actors who played them. The Star Trek franchise has a history of attracting high-caliber talent, and a strong guest star can make the simplest of stories become something great. With a single appearance, these actors delivered memorable performances that made their episodes instant classics.
10 Famke Janssen As Kamala
Star Trek: The Next Generation Season 5, Episode 21 - "The Perfect Mate"
When the USS Enterprise-D transports an empathic metamorph named Kamala, Captain Picard develops feelings for the young woman. Kamala can become whatever type of woman the men around her want her to be, but she gets to be herself with Picard. Despite the budding feelings between Kamala and Picard, Kamala has already been promised to a Valtian ambassador in an arranged marriage.
The gender roles depicted in "The Perfect Mate" feel outdated for the 1990s, but Famke Janssen's performance makes Kamala work as a character even if the episode's premise is faulty. Picard and Janssen play off of one another well, both delivering compelling and believable performances. While it would have been nice to see what became of Kamala after her arranged marriage, Janssen made the character memorable.
9 Billy Campbell As Captain Thadiun Okona
Star Trek: The Next Generation Season 2, Episode 4 - "The Outrageous Okona"
When the Enterprise picks up Captain Thadiun Okona to help repair his ship, the charismatic "rogue" charms the ship's crew and romances multiple women on board. When leaders from two different planets claim that Okona has wronged them, Captain Picard finds himself caught up in a family squabble that Okona eventually helps resolve. While Okona could have come across as creepy or cringe-inducing, Billy Campbell makes the character work.
Although Captain Okona only appeared once in TNG, he did pop up in three episodes of Star Trek: Prodigy and appeared in the background of an episode of Star Trek: Lower Decks.
After seeing the way Okona makes the Enterprise crew members laugh, Lt. Commander Data (Brent Spiner) attempts to understand humor. While Brent Spiner is great as always, this subplot does not work as well as it could have. Still, the episode is memorable thanks to Billy Campbell (who was considered for the role of Commander Will Riker before Jonathan Frakes landed the part). Plus, the reveal that Okona has been helping two star-crossed lovers communicate only makes the character more likable.
8 Matt Frewer As Berlinghoff Rasmussen
Star Trek: The Next Generation Season 5, Episode 9 - "A Matter of Time"
As the Enterprise travels to Penthara IV, they encounter a time traveler named Professor Berlinghoff Rasmussen who claims to be a researcher from the 26th century. As the crew grows increasingly annoyed by Rasmussen's interviews, they begin to suspect he may be hiding something. When Captain Picard discovers that several items from the Enterprise have gone missing, he confronts Rasmussen.
The role of Professor Rasmussen was originally written for Robin Williams, but he was busy filming Steven Spielberg's Hook.
Rasmussen eventually reveals himself to be an inventor from the 22nd century who stole a time machine from a 26th-century time traveler. When Picard detains Rasmussen, his time pod disappears, standing him in the 24th century. A skilled character actor, Matt Frewer brings a perfect faux-charming smug energy to Rasmussen that makes him entertaining and fun to watch, if not particularly likable as a character.
7 Beth Toussaint As Ishara Yar
Star Trek: The Next Generation Season 4, Episode 6 - "Legacy"
When the Enterprise answers a distress call from a Federation freighter near the planet Turkana IV, they must work with the planet's inhabitants to save the freighter's crew. When one of the planet's two warring factions offers to help Picard and his crew retrieve the survivors, they send Ishara Yar to act as a liaison. Ishara is the younger sister of Lt. Tasha Yar (Denise Crosby), who served as the Enterprise Security Chief until Tasha's untimely death in TNG season 1.
After a DNA test confirms Ishara to be Tasha's sister, Picard and the Enterprise crew put their trust in her, and she forms a friendship with Data. In the end, however, Ishara was actually just using the Enterprise as a means to orchestrate an attack on the opposing faction. "Legacy" may have its flaws, but Beth Toussaint delivers a compelling performance as Ishara, offering a glimpse into Tasha's life before Starfleet.
6 David Ogden Stiers As Dr. Timicin
Star Trek: The Next Generation Season 4, Episode 22 - "Half A Life"
In one of Lwaxana Troi's (Majel Barrett) best Star Trek episodes, the Starship Enterprise hosts Troi alongside Dr. Timicin of Kaelon II. As the Enterprise crew helps Timicin conduct experiments that he hopes will save his planet, he forms a bond with Lwaxana Troi. Timicin soon reveals that everyone on his planet is required to end their life at the age of 60, and Timicin is quickly approaching his 60th birthday.
Lwaxana, who has begun to develop feelings for Timicin, is understandably upset by this news. She calls the practices barbaric and urges Captain Picard to intervene, but he refuses due to the Prime Directive. In the end, Lwaxana accepts Timicin's choice to go through with the process, even accompanying him to the ceremony. With his nuanced performance, David Ogden Stiers makes Timicin a fully realized character who helps humanize the more outlandish Lwaxana.
5 Harry Groener As Tam Elbrun
Star Trek: The Next Generation Season 3, Episode 20 - "Tin Man"
In this excellent Data-centric Star Trek: The Next Generation episode, a Betazoid Federation emissary named Tam Elbrun comes aboard the Enterprise-D to initiate first contact with a strange alien. Because of his extraordinarily strong telepathic abilities, Elbrun is overwhelmed by the thoughts of the people around him. He forms a connection with Data because he cannot hear the android's thoughts and has to get to know him the old-fashioned way.
Upon contacting the living alien ship known as Tin Man, Elbrun connects with it, too. He ultimately chooses to remain with Tin Man and leave his old life behind. Harry Groener makes Elbrun a sympathetic character, even as he interrupts the Enterprise crew members by reading their thoughts. Groener perfectly conveys Elbrun's exhaustion with the world and his wonder at meeting Data and then Tin Man.
4 Paul Winfield As Captain Dathon
Star Trek: The Next Generation Season 5, Episode 2 - "Darmok"
"Darmok" is a classic Star Trek: The Next Generation episode where Captain Picard finds himself stranded on a deserted planet with a Tamarian captain named Dathon. Because the Tamarians speak in metaphors that require a knowledge of their history, Picard and Dathon cannot understand one another. As they work to find ways to communicate, they are attacked by a creature from the planet and Dathan is seriously wounded.
Although Picard and Dathan eventually develop an understanding with one another, Dathan ultimately succumbs to his injuries. Despite their captain's death, the Tamarians are glad that Picard has found a rudimentary way to communicate with them. It takes a strong actor to play against Patrick Stewart, and Paul Winfield is certainly up to the task. He conveys so many emotions as Dathon, from frustration to excitement, all while speaking in a nonsensical language.
3 Saul Rubinek As Kivas Fajo
Star Trek: The Next Generation Season 3, Episode 22 - "The Most Toys"
When the Enterprise meets with Kivas Fajo, the collector kidnaps Data and fakes his death. Fajo collects rare artifacts and wants to add Data to his collection. Data remains defiant until Fajo threatens to kill his assistant, Varria (Jane Daly), unless the android complies. Varria later helps Data escape, but Fajo catches them and kills her. Having realized Fajo's deception, the Enterprise returns to rescue Data.
Saul Rubinek delivers a stellar performance as Fajo.
In one of Data's most human moments, he appears to fire a phaser at Fajo just as the Enterprise beams him back to the ship, despite the subroutines that should prevent the android from killing. Saul Rubinek delivers a stellar performance as Fajo, making him one of Star Trek's slimiest characters. The energy between Brent Spiner and Rubinek crackles as they practically fling their often snarky lines at one another, and it's incredibly satisfying when Fajo finally ends up in the Enterprise's brig.
2 James Sloyan As Admiral Jarok
Star Trek: The Next Generation Season 3, Episode 10 - The Defector"
Captain Picard and his crew are initially skeptical when they encounter a self-proclaimed Romulan defector who eventually reveals himself to be a notorious Admiral named Jarok. As Picard tries to figure out whether Jarok's claims of an imminent Romulan invasion are true, Data treats the Romulan with kindness, showing him his home plane on the holodeck. When the Enterprise-D travels to Nelvana III to investigate Jarok's claims, they learn that the Romulans had fed Jarok incorrect information.
Having realized he abandoned his home and his family for nothing, Jarok takes his own life. Throughout "The Defector," James Sloyan portrays Jarok with perfect subtly as the Romulan works to convince Picard to believe him. With his courageous decision to abandon his home to prevent a war and his regret that he will never see his family again, Jarok is a tragic figure who ultimately helps humanize the Romulans as a species.
1 David Warner As Gul Madred
Star Trek: The Next Generation Season 6, Episodes 9 & 10 - "Chain of Command"
In one of Star Trek: The Next Generation's most brutal storylines, Cardassians kidnap Captain Picard and torture him for information about the Federation. Gul Madred oversees Picard's interrogation, subjecting him to various forms of torture in an intense battle of wills. Madred eventually places four lights in front of Picard and demands the Enterprise captain answer that there are five lights.
Warner's performance is even more impressive considering he only had a few days to prepare.
Captain Picard refuses to break, and Patrick Stewart is a tour-de-force in one of his best Star Trek: The Next Generation performances. But David Warner more than delivers as his scene partner, making Madred truly menacing. Warner's cold and calm demeanor as Madred plays perfectly against Stewart's desperation as Picard. Warner's performance is even more impressive considering he only had a few days to prepare after the original actor dropped out unexpectedly.
