!!Jason Nesmith/Captain Peter Quincy [=McTaggart=]
->Played By: Creator/TimAllen

An actor who once starred as the captain in a sci-fi show named ''Film/GalaxyQuest''. He's arrogant, seemingly a jerk to his costars, and is stuck in the past, clinging to the old glory days of the show, enabled by the devoted fans who love his showboating antics. At the beginning of the movie, at yet another convention, Nesmith is confronted with how pathetic he has become and drinks himself into a stupor. It's in this state that he encounters the aliens and unwittingly agrees to his first real mission.

* {{Badass}}: All those years of rolling around a soundstage covered in dirt really paid off.
* BreakTheHaughty: At the start of the film, he realises how pathetic he's become.
* TheCaptain: His position in the show, which means he gets giddy when he gets to be an ''actual'' captain.
* TheCharmer: With his fans, yes. With his fellow actors... not so much.
* GuileHero: He's got a good head for tactics.
* HiddenDepths: He is a bit arrogant at first, but he eventually shows a nicer side.
* TheKirk: His role in the show.
* JumpedAtTheCall: Once the interstellar shakes wear off, he's thrilled that a bunch of real, actual aliens built a replica of the ship and consider the cast to be actual heroes.
* LargeHam: Much to the annoyance of his fellow actors.
* TheLeader: His position on the show, and he eventually takes the position for ''real''.
* NoCelebritiesWereHarmed: To William Shatner, the show's main cast member who has an inflated ego and is shocked to discover how the rest of the cast dislikes him for it.
* TookALevelInKindness: Contrast his appearances at the beginning and at the end of the film; at the beginning he's unashamedly hogging the spotlight and gets disappointed when he doesn't get the fanfare he wants. At the end, he realises that the crowd at the convention aren't paying his costars any attention, and gestures for them all to come up and share the spotlight as they deserve it.
* UnnecessaryCombatRoll: He does this on the away mission before any actual danger occurs, out of habit from doing it on the show. It doesn't actually help him at first, and even causes him to lose his weapon. [[spoiler:It helps him kill Sarris in the end.]]
-->'''Gwen:''' [[SarcasmMode Does the rolling help]]?
-->'''Jason:''' Uh huh. It helps.
-->'''Gwen:''' ''*smirking*'' Where's your gun?
-->'''Jason:''' ...Shit!
-->'''Alexander:''' [[SarcasmMode "It helps."]]
* WhatHaveIDone: [[spoiler: After he tells Mathesar the truth about the show not being real.]]

!!Gwen [=DeMarco=]/Lt. Tawny Madison
->Played By: Creaator/SigourneyWeaver

Another star of the show ''Film/GalaxyQuest'' now trapped on the convention circuit. Gwen played the show's fanservice character and is resigned to the idea that she never gets taken seriously. On the show, she had superfluous job of repeating the computer's statements and repeating the orders of the captain to the computer, so when the aliens build a real version of the ship, she gets stuck with that job again. There's some indication that Gwen and Jason were once genuinely attracted to each other but it died quickly once Gwen figured out what kind of guy Jason really was.

* ActionGirl: Though not in the old show, much to her chagrin.
* BridgeBunny: "I repeat everything the computer says".
** To the point that the computer only responds to her questions!
* CommunicationsOfficer: She does this during the movie out of principle--it's her one job, and she will do it even though it's stupid.
* TheLancer: Alexander is the lancer on the show, but in ''real life'' Gwen fills the role.
* ImpossiblyLowNeckline: She '''''HATES''''' it!
* LimitedAdvancementOpportunities: She just repeats what the computer says, and she '''''HATES''''' that too!
* NoCelebritiesWereHarmed: To Nichelle Nichols in her role as a bridge officer, and Jeri Ryan in being a skilled actress trapped as a shameless MsFanservice character (and unlike Ryan, never being able to break out of that role).
* SarcasticDevotee: To Nesmith.

!!Sir Alexander Dane/Dr. Lazarus of Tev'Meck.
->Played By: Creator/AlanRickman

Lazarus is a "Mak'tar", a member of an alien species renowned for their intellect. He is deeply intelligent and has psionic abilities. Additionally, he has a non-standard weapon and a pretentious catchphrase: "By Grabthar's hammer, by the suns of Warvan, you shall be avenged!". A trained Shakespearean British actor, Alexander resents both his catchphrase and being typecast.

* AlwaysSecondBest: To Jason.
* {{Catchphrase}}: "By Grabthar's hammer, by the suns of Warvan, you shall be avenged!" Ironically enough he hates it.
** Also serves as an IronicEcho, a TearJerker and a PreAsskickingOneLiner [[spoiler:(when he speaks the line to comfort a dying Quellek, who considered him a father figure)]].
--> '''Alexander''' (gentle, but with gravitas):"By Grabthar's hammer... by the suns of Warvan, you ''shall'' be... ''' ''avenged'' '''."
* ClassicallyTrainedExtra: ''Bitter'' about it, too.
* DeadpanSnarker: It helps that he is played by Alan Rickman.
* HiddenHeartOfGold: When [[spoiler:Quellek is shot]], Alexander delivers his catchphrase with complete sincerity, after having earlier stopped him from reciting it.
* HumanAlien: Subverted; the alien part really is just makeup.
* INeedAFreakingDrink: When asked where he's going after the traumatic first contact with Sarris, he shouts back "to see if there's a pub."
* JerkassFacade: He comes across as rather annoyed and cynical by everything, but at the end of the day he's a good guy.
* NoCelebritiesWereHarmed: Part Creator/LeonardNimoy (bitter about being [[IAmNotSpock typecast as Lazarus]]- Nimoy got over it, though ), part Creator/PatrickStewart and part Alec Guinness- a respected Shakespearean actor who ended up on a cult science fiction show, and is none too happy about it (Stewart doesn't regret his time on ''Franchise/StarTrek'' and in fact, is proud of his role, but Guinness was upset that many people only remembered him from ''Franchise/StarWars'').
* NotSoAboveItAll
* TheSpock: The character on whom he's based.
* TookALevelInBadass: He charges an alien head-on while unarmed and ''wins''.

!!Tommy Webber/Lt. Laredo
->Played By: Daryl Mitchell

Tommy parodies an actor in the "boy wonder" role, who has aged considerably since he was on the show. His role as Laredo is essentially that of the pilot, but when he flies the real ''Protector'' out, it takes him most of the film (and carefully studying his old ''Galaxy Quest'' episodes) to remember how to do it right.

* AcePilot: In the show; not so much in real life.
* DoingItForTheArt: This occurs in-universe as, due to the fact that he was a kid at the time, he naturally took his role on the show quite seriously, to the point of coming up with his own consistent method of how the ship's controls worked. This comes in handy when the Thermians recreate the ship from the episodes.
* {{Expy}}: Of Wesley Crusher from ''Series/StarTrekTheNextGeneration''. WilWheaton (the actor who played Wesley) commented that the one aspect of ''Trek'' fandom the film lacked was a fan complaining about the presence of a kid on the bridge. (In fact, Wheaton would have liked to [[TheCameo play the role himself]].)
* KidAppealCharacter: On the original show, he was about ten years old.
* TeenGenius: His character.
* TookALevelInBadass: "Pedal to the medal!"

!!Fred Kwan/Tech Sgt. Chen.
->Played By: Tony Shaloub

Chen is in charge of the engine room and the operator of the "digital conveyor" (a version of the ''Franchise/StarTrek'' transporter). He acts in a detached manner and is completely unfazed by the strange and often disturbing events that occur.

* BunnyEarsLawyer: He may be a little nuts or detached but he's good at what he does... eventually.
* {{Cloudcuckoolander}}: His spacey attitude (no pun intended). A cut scene indicated the [[TheStoner reason behind this]].
* GreaseMonkey
* FakeNationality: "Kwan's not even my real name!" In-universe, he's an actor who plays a guy who changed his name then played a guy who is fake. In the process, the real actor played a guy who played a guy and must become that guy even though he's fictional.
* HeroicBSOD: He freaks out when he's asked to operate the "digital conveyor," which could kill Jason if he does it wrong.
* InterspeciesRomance: He eventually falls in love with a Thermian.
* LovableNerd: In reality, he's only a ''Hollywood'' nerd.
* MacGyvering
* MrFixit
* NoCelebritiesWereHarmed: To James Doohan, playing the engineer with an obvious case of FakeNationality (here made even more obvious by his playing a different ''race'').
* ObfuscatingStupidity: Or maybe not; frankly, it's hard to tell.
* TheStoner: It's cut out for the most part, but he is explicitly asked whether he's high at one point.
* UnfazedEveryman: He genuinely doesn't seem that freaked out by the events around him... aside from his doubts about successfully operating the digitizer.

!!Guy [[spoiler:Fleegman]]/Crewman #6/[[spoiler:Security Chief Roc Ingersoll in the new Galaxy Quest]]
->Played By: Creator/SamRockwell

An actor who played an extra in one episode of ''Film/GalaxyQuest''. He suffers from paranoia that he will end up in a {{Red Shirt}}'s [[HesDeadJim natural state]] during the film. The character is based on real-life ''Franchise/StarTrek'' actor Guy Vardaman, who played an uncredited background character.

* {{Adorkable}}: Nearly two decades after his cameo on the show, he's still nothing but proud of it and perfectly satisfied with this tiny blip of a career.
* AscendedExtra: From no name redshirt [[spoiler: to chief of security]] in-show, of course.
* ButtMonkey
* GenreSavvy: "Didn't you guys ever ''watch'' the show?"
* OnlyOneName: For most of the movie, which he uses as prime evidence of his unlikelihood to survive.
-->'''Gwen:''' Guy, you ''have'' a last name.
-->'''Guy:''' ''Do I?'' ''DO I?!''
* PluckyComicRelief: Possibly, according to Kwan. [[spoiler: Realising that he's this and not a redshirt is a great relief to him.]]
* RedShirt: On the show, he got killed by a lava monster shortly into the episode. [[spoiler: However, he's never killed off!]]

!!Sarris
->Played By: Creator/RobinSachs

A genocidal alien warlord, Sarris is the force that ultimately causes the Thermians to seek the Galaxy Quest team out for help. When he turns up, things get a lot worse.

* AxeCrazy: The guy is slightly nuts.
* BadBoss: The man decapitated his previous [[TheDragon lieutenant]] for failing to raise the shields in time. He then leaves several loyal soldiers to die on the Thermian ship.
* BigBad: The one behind the whole storyline kicking off.
* [[spoiler:CharacterDeath: He dies when Jason shoots him and he is disintegrated.]]
* ColdBloodedTorture: He did this to the Thermian commander who preceded Mathesar.
** ForTheEvulz: He already had the information he needed and explicitly invokes this trope, albeit not by the name it has on this very site.
-->'''Thermian Commander:''' ''I have told you all I know... please... if you have any mercy, let me die.''
-->'''Sarris:''' ''I shall kill you when I grow tired of the noises you make!''
* DangerouslyGenreSavvy: In his first fight with the heroes, he opts to drive them into a minefield which causes them to be severely crippled. Later, [[spoiler:he disguises himself as Fred with an image inducer, sneaks onto the ship and kills pretty much everyone except Guy. This is only undone by the Omega 13, which he had no way of knowing about]].
* EvilBrit: Played by Robin Sachs.
* EvilIsHammy: He generally gets a bit loud, though it's often terrifying instead of funny. When he stops being hammy, he's ''really'' serious.
* EyepatchOfPower: Gains one after the first attempt to deal with him fails.
* GallowsHumor: Leading to possibly his only funny moment in the entire film.
--> ''Jason'': Hey Sarris, how're you doing?
--> ''Sarris'': (shows the head of his lieutenant mounted on a stick) Better than my lieutenant!
* GenreSavvy: Being a ''real'' alien overlord, the actors of the show have a very difficult time dealing with him because he's actually competent and intelligent. Really, the only two mistakes he makes are assuming the actors and Thermians are too emotionally broken to stop the ship's self-destruct sequence, and not realizing [[spoiler:the ''Protector'' was dragging a field of magnetic mines towards his ship.]] When he finally sees the "historical documents", Sarris immediately realizes what's happened and has a jolly laugh over it, then forces Jason to tell Mathesar the truth, knowing the revelation will break his spirit harder than anything Sarris himself could ever do.
* HandicappedBadass: He's horribly cruel and very depraved, but the guy is a good straight-up fighter in spite of lacking one eye.
* KickTheDog: Oh, where to begin.
* KnightOfCerebus: After it turns out that he's actually a real threat and not something from a B-movie, the humour rating drops significantly whenever he's onscreen.

!!Mathesar
->Played By: Enrico Colantoni

The leader of the Thermians, though he steps back to let Jason lead. He and his other people are completely ignorant of any type of falsehood, including fictionalized entertainment, and thus they have no idea that ''Galaxy Quest'' was just a TV show.

* BreakTheCutie: When Jason finally tells him the truth, Mathesar is broken almost beyond the point of speech.
* MrExposition: By virtue of AsYouKnow -- Mathesar is eager to show the crew how perfectly they've replicated the ''Protector'', thus explaining the ship's functions to the audience as well.
* StrangeSyntaxSpeaker[=/=]WhatTheHellIsThatAccent: Thermians speak a language ''very'' different from English. They use translators to get around this, but their speech still comes out very stilted and strange, somewhere between these two tropes.
* YouAreInCommandNow: When the actors leave at last, Jason appoints Mathesar Commander of the ''Protector''.

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