-> Played by Tommy Wiseau
* AteHisGun: Shoots himself in despair after he locks himself in the titular room and trashes the place.
* BettyAndVeronica: The Betty to Mark's Veronica for Lisa's Archie
* {{Catchphrase}}:
** Oh hai, X.
** That's the idea!
** "Don't worry about that/it." Says this to things people would typically worry about, with variations.
* ColdHam: Thanks to Wiseau's horrible acting. Even when Johnny is screaming and going over the top, he sounds bored with his dialogue.
* DullSurprise: "I did not hit her, it's not true. It's bullshit, I did not hit her! I did NAAAGHT... Oh hi, Mark."
%%* FourTemperamentEnsemble: The Melancholic.
* EyesAlwaysShut: His eyes are usually halfway closed for whatever reason.
* {{Gonk}}: Tommy Wiseau isn't as attractive as he thinks he is.
%%* TheHero
* TheHyena: "Ts-Hahahahahahahahaha."
* LargeHam: Somehow manages to overlap this with DullSurprise.
* LipLock: Has a ''bad'' case of it.
* LooksLikeCesare: Black hair, and an appearance that suggests he doesn't go outside much.
* NiceGuy: Lets see, he apparently buys Lisa a dozen red roses every time they make love, or at least often enough to be the flower shop lady's favorite customer, and would do anything for. He's paying for Denny's college and tuition without asking for anything in return. Is incredibly nice to all of his friends and seems to only want to make Lisa happy.
%%* RapunzelHair
* TheTeetotaler: The exception being the [[GargleBlaster Scotchka]] scene.
* TooGoodForThisSinfulEarth
* TookALevelInJerkass: Towards the end of the movie, starting with the fight between him and Mark as he discovers that Lisa is cheating on him during his birthday party.
%%* UnstoppableRage
* WhatTheHellIsThatAccent: Especially funny since it's Tommy Wiseau's natural accent.
* YouNoTakeCandle: Slips into this at times, most notably "Everybody betray me! I fed up with this world!"

-> Played by Juliette Danielle

* BrainlessBeauty: Her schemes aren't very well thought out.
* BeautyIsBad: Gives this impression.
* BitchInSheepsClothing: She seems nice, at first. Then we find out that she's cheating on her loving [[InsistentTerminology future spouse]] because she's ''bored'' with him.
* {{Catchphrase}}:
** "I don't want to talk about it"
** "Don't worry about it."
* CharacterShilling: Many characters will stop whatever momentum the movie has in order to talk about how great Lisa is.
* TheChick: Right down to being in a LoveTriangle with TheHero and TheLancer.
* {{Determinator}}: Juliette Danielle is, at least. Knowing all the abuse, degradation, and humiliation she endured while making the film, it's truly amazing that she got through it at all.
* DisproportionateRetribution: She's cheating on Johnny because ''she thinks he's boring''.
* DumbBlonde: In a way. Most notably not caring about the fact that if she continues cheating, she's going to destroy Johnny, despite Stevens serious words to her.
%%* FourTemperamentEnsemble: The Choleric.
* InformedAttractiveness: Lisa's actress isn't ugly, but she still does not quite live up to how beautiful all the men act like she is.
* HelloNurse: Barely a scene goes by where someone doesn't comment on her attractiveness.
* HotGirlsAreBitches: She's as pretty as she is reprehensible.
* ItsAllAboutMe: Case in point, after her future spouse [[spoiler:commits suicide]], her first action is to tell the guy she was cheating on him with (who also happened to be his best friend) that they can finally be together. Mark rightfully calls her out on this.
* {{Jerkass}}: Cheats on her loving future spouse with his best friend because she's bored with him, was implied to have just been using him for money in the first place, lies about him abusing her to justify it and [[spoiler:''tells his best friend that there is nothing between them after Johnny kills himself'']]. At the end, Mark finally grows a spine and tells her off for it.
* {{Manipulative B|astard}}itch: Dear God, Lisa. Mark flat-out lampshaded this.
* PetTheDog: Despite her nastiness, Lisa seems to genuinely care for Denny
* SatelliteLoveInterest: As the girlfriend, her scenes are limited to having sex and sitting on a pedestal. As the antagonist, she's the axis of the whole film.
* SmugSnake: Sure Lisa, be all secretive and paper thin with your lies and cheating. Johnny will ''[[SarcasmMode never]]'' find out.
* StupidEvil: She makes quite a few mistakes during the movie.
* TheUnfairSex: {{Inverted|Trope}}; everyone acts like the affair is her fault while downplaying Mark's role. Though she was the one throwing it in people's faces.
* YourCheatingHeart: Cheating on Johnny with Mark.

-> Played by Greg Sestero

%%* BeautyIsBad
* BettyAndVeronica: The Veronica to Johnny's Betty for Lisa's Archie
* DullSurprise: His reaction every time Lisa invites him over "[[IsThatWhatTheyreCallingItNow to talk]]" and then winds up trying to sleep with him.
* FlatCharacter: [[WordOfSaintPaul Greg Sestero himself]] views Mark this way. [[https://www.reddit.com/r/IAmA/comments/1nbna6/oh_hai_mark_greg_sestero_mark_from_the_room_here/cch41ra?context=1 According to him, any time he tried to add any depth to the role, Tommy would accuse him of trying to be king of the world.]]
* FourTemperamentEnsemble: The Phlegmatic.
* ImAManICantHelpIt: The presumed explanation for TheUnfairSex below.
* ImportantHaircut: Subverted. He shaves his beard and everyone makes a big deal out of it, but it doesn't signal a change in character.
* TheLancer: He's Johnny's ''best friend''.
* MarijuanaIsLSD: Becomes uncharacteristically violent and belligerent after taking just a couple hits from a joint.
%%* MrFanservice
* TheStoner: A hilariously ill-written variation. See MarijuanaIsLSD above.
* {{Tuckerization}}: Attempted. According to ''Literature/TheDisasterArtist'', Tommy named Mark after the lead actor of Film/TheTalentedMrRipley "[[Creator/MattDamon Mark Damon]]".
* TheUnfairSex: {{Inverted|Trope}}; everyone acts like the affair is entirely Lisa's fault.

-> Played by Philip Haldiman

* AmbiguousDisorder: His behavior is... incredibly bizarre for someone who is likely pushing his twenties. Even Tommy Wiseau has admitted the character makes more sense if you think of him as mildly retarded.
* CompressedVice: His drug dealings with Chris-R are brought up once and then never again afterward.
%%* FourTemperamentEnsemble: The Sanguine.
%%* KidAppealCharacter
* ManChild: To a degree. He keeps trying to go upstairs with Johnny and Lisa when he knows they're going to have sex, and presumably wants to join in, then follows them upstairs and jumps on the bed. He also talks about how he's "in love" with Lisa like a 7-year old, and fawns over her to a creepy effect.
* NoSocialSkills: "I just like to watch you guys."
* PhraseCatcher: "Oh hai, Denny!"
* PrecisionFStrike: Against Claudette.
* TagalongKid: Denny doesn't have much importance to the plot.

-> Played by Carolyn Minnott

* AngerBornOfWorry: She tears into Denny after she discovers that he was nearly killed by a drug dealer that he owed money to, though she seems to care for Denny's well being in the end.
* BrutalHonesty: She flat-out admits to Lisa that she hated her ex-husband who's Lisa's father.
* GoldDigger: She certainly believes that women should aspire to be this and more or less states that it's the only reason she married Lisa's father.
** She even mentioned how she tried to sponge off Johnny.
* HypocriticalHumour: She states in one sentence how much she [[StrawFeminist dislikes men]], and states in the next sentence that men and women exploit each other.
* TheMentor: The closest thing this movie has to one. Naturally, she's very bad at it.
* OnlySaneWoman: She may be an immoral, self-absorbed hypochondriac, but she's also the only character in this movie who seems even remotely aware of how absurd the plot is.
* PragmaticVillainy: She wants Lisa to marry and be faithful to Johnny so that she can [[GoldDigger live off]] a stable life with him. This ends up with an extreme case of VillainHasAPoint: [[spoiler: If Lisa had listened to her mother, it would have been for the better for ''everyone involved!'' [[DrivenToSuicide Johnny wouldn't have committed suicide]], he and Mark would still be friends, Danny would still receive college tuition, Lisa would, again, live a good life and the flower shop would still have their favourite customer.]]
* StrawFeminist: She has a very low opinion about men, but she's at least open-minded enough to know that women can also be manipulative.
* WhatHappenedToTheMouse: Her breast cancer. It comes up once, then is never mentioned again.
--> "They have cures for everything."
** WordOfGod confirms that [[spoiler:she'll live through it]].

-> Played by Scott Holmes (credited as Mike Holmes in the film, due to Wiseau forgetting the actor's name)

* BetaCouple: With Michelle.
* LargeHam: He's no louder than the rest of the cast, but his exaggerated facial expressions and non-stop mugging have to be seen to be believed.
* PluckyComicRelief

-> Played by Robyn Paris

* BetaCouple: With Mike.
* [[OnlySaneMan Only Sane Woman]]: The most level-headed of the cast, along with Peter. She knows how destructive Lisa's infidelity is and tries to talk her out of it several times.
** Also the only character who doesn't say "don't worry about it" or "everything's going to be fine".
** And she's the only female character who seems to be a decent person.

-> Played by Dan Janjigian

%%* TheAggressiveDrugDealer
* ChandlersLaw: He starts the first violent part of the movie.
* ClusterFBomb: "Where's my FUCKIN' MONEY DENNY?!"
* GangstaStyle: How he holds his gun.
* GiantSpaceFleaFromNowhere: He isn't really referenced until he shows up to try and get Denny to pay him. [[WhatHappenedToTheMouse After that, he is never mentioned or referenced again]].
%%* HotBlooded
* LargeHam: According to ''Literature/TheDisasterArtist'', Dan gave what's considered the most passionate performance in the movie.
* NoIndoorVoice: To be fair, he was outside when he was doing all his yelling. Though presumably being inside wouldn't have stopped him.
%%* SirSwearsalot
%%* SleevesAreForWimps

-> Played by Kyle Vogt

%%* BrainySpecs
* BusmansHoliday: Is still playing the Psychologist even when he's off-duty.
* ChuckCunninghamSyndrome: Mysteriously disappears midway through the movie, and is never mentioned again.
* OnlySaneMan: [[TookTheBadFilmSeriously Even in real life]].
%%* TheSmartGuy
* WhatHappenedToTheMouse: His actor quit mid-movie, so he disappears and Steven takes his place.

-> Played by Greg Ellery

* AllThereInTheScript: His name is only known by the credits.
* EleventhHourRanger
-->[[Podcast/RiffTrax "Um, I'm sorry. Should we know who you are? Hello?"]]
%%* LargeHam
* RealLifeWritesThePlot: He only exists because Peter's actor quit.
* RememberTheNewGuy: An impossibly lazy example. With about 20 minutes left in the movie, a new character suddenly appears and becomes deeply involved in the plot. Presumably, we're not supposed to notice that he suddenly appeared from nowhere without an introduction. WordOfGod is that Steven is supposed to be a replacement for the psychologist character Peter (whose actor left the production), but the audience is given no hint of this; indeed, Steven looks nothing like Peter.
* SuspiciouslySimilarSubstitute: Originally, Peter had Steven's role, but his actor quit during filming, leading to Steven's creation.

-> AsHimself

* ADogNamedDog: A Doggie named Doggie, specifically.
* AsHimself
* PreciousPuppy
%%* TeamPet

!!Flower Shop Lady

%%* AmbiguouslyGay
* FailedASpotCheck: She fails to recognize Johnny until he takes off his sunglasses.


Claudette's brother (and Lisa's uncle), who wants her to give him a share of her house. Claudette is less than willing to do this.

* TheGhost: Along with Shirley Hamilton.
* {{Jerkass}}: According to Claudette.

!!Shirley Hamilton

Claudette's friend, who wants to buy a new house. Claudette asks Johnny to help her with a down payment, only for him to tell her it's an awkward situation. She expected him to be more generous. The only character in the entire movie to have a surname, yet she's entirely offscreen.

* TheGhost: Along with Harold.