Believe it or not, George Costanza is a massive Trekkie.
Most people know Jason Alexander as the neurotic, jacket-throwing best friend on Seinfeld, but his heart belongs to the stars. Specifically, to the bridge of the Enterprise. He didn't just want a cameo for the paycheck or the credit; he spent years practically begging the producers to let him into the universe. But there was a catch. He didn't want to be human.
The Time George Costanza Met Captain Janeway
In 1999, just about a year after Seinfeld went off the air, Alexander finally got his wish. He appeared in the Star Trek: Voyager episode "Think Tank" (Season 5, Episode 20) as an alien named Kurros.
Honestly, it’s one of the best "against type" performances in the whole franchise.
Usually, when a sitcom star jumps into sci-fi, they bring a bit of that "funny man" energy with them. Not here. Kurros is the leader of a small group of hyper-intelligent aliens who wander the Delta Quadrant solving impossible problems for a price. He’s soft-spoken. He’s chillingly calm. He is the polar opposite of the man who once screamed about "the summer of George."
Why Kurros was the perfect role
Before Voyager called, Alexander had actually turned down other Star Trek offers. Why? Because the writers kept trying to cast him as a "George-like" human. They wanted him to be the bumbling comic relief or the annoying bureaucrat.
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Alexander hated that idea.
He told the producers he wanted to play a Vulcan or something with a "great intellect." He wanted to escape the "histrionics" of his sitcom days. When the script for "Think Tank" landed, it gave him the "trifecta" he was looking for:
- A complete alien transformation.
- A character with a genius-level IQ.
- A subtle, manipulative streak of evil.
That Iconic Makeup and the Kirk Obsession
If you watch the episode, you barely recognize him. He’s covered in heavy prosthetics—a bulbous, textured head and pale, mottled skin. In interviews with StarTrek.com, he mentioned the makeup took about two and a half hours to apply. Even worse? It took forever to take off after a 12-hour day on set.
But he loved it.
Alexander has been a devotee of The Original Series (TOS) since he was ten years old. He’s gone on record saying that William Shatner’s Captain Kirk actually informed his own acting style. He once joked that as a "staunch heterosexual," Shatner still "rang his bell." He studied Kirk’s pauses, his confidence, and his authority.
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Interestingly, he saw those same qualities in Kate Mulgrew. He famously referred to Captain Janeway as the "bastard step-child of Kirk," which is probably why he enjoyed his scenes with her so much. The chemistry between Kurros and Janeway is tense because they are playing a high-stakes game of chess, and Alexander plays the villain with a terrifyingly quiet dignity.
The Inside Joke Most Fans Missed
There is a legendary "Easter egg" in this episode that connects Seinfeld to Star Trek.
In the Seinfeld episode "The Seven," George is obsessed with the name "Seven" for his future child. He thinks it’s beautiful, unique, and powerful.
Fast forward to Voyager.
When Kurros is trying to recruit Seven of Nine to join his Think Tank, he looks at her and says, "Seven... it's a beautiful name."
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It’s a tiny, blink-and-you’ll-miss-it moment, but for fans of both shows, it’s a stroke of genius. It was a meta-wink to the audience that Alexander was fully aware of his sitcom legacy even while buried under pounds of latex.
He Came Back for More (Eventually)
For decades, Kurros was Alexander's only contribution to the canon. But the "Trek bug" is real.
In 2022, he finally returned to the franchise, but this time in the animated series Star Trek: Prodigy. He voiced Dr. Noum, a Tellarite medical officer. Tellarites are notoriously argumentative and stubborn, which allowed Alexander to use a bit more of his "grumpy" energy while still remaining firmly in the alien camp.
He ended up appearing in over 20 episodes of Prodigy, fulfilling his dream of being a recurring part of the Starfleet world.
What You Can Do Now
If you haven't seen "Think Tank" in a while, it's worth a rewatch just to see how much Alexander disappears into the role. It’s currently streaming on Paramount+.
- Watch for the subtlety: Pay attention to how he uses his eyes. Since his face is covered in rubber, he has to do all the emotional heavy lifting with his gaze and his voice.
- Check out the 1999 Special: Look up "Ultimate Trek: Star Trek's Greatest Moments." Alexander hosted it and actually got to play Captain Kirk in a series of sketches. His Shatner impression is surprisingly spot-on.
- Compare the voices: Listen to Kurros in Voyager and then listen to Dr. Noum in Prodigy. The range he has as a voice actor and a physical performer is much wider than the "Costanza" box people usually put him in.
The legacy of Jason Alexander in Star Trek is a reminder that even the biggest stars are often just big nerds at heart. He didn't show up for a "celebrity cameo." He showed up because he genuinely loved the world Gene Roddenberry built.