!![[GameShowHost And now, our hosts...]]

!!!'''Cookie Masterson'''
->''"Hello, people! How ya doin'? My name's Cookie, welcome to our show here. How many people are gonna be playing the game?"''
-->-- One of Cookie's first lines upon starting a game, ''Volume 1''

-->'''Voiced by:''' Tom Gottlieb

The most well-known host. Started his career as the green-room organizer in ''Volume 1'', ''Sports'' and ''Volume 2'', before going on to to host ''Movies'', ''Volume 3'', the ''Netshow'', the UsefulNotes/PlayStation game, part of ''The Ride'', ''Offline'', the online game, ''2011'', the first iOS game, the Website/{{Facebook}} game, [=OUYA=], ''Party'', and ''2015'' . Also the green-room organizer in German Volume 1, German Volume 2, German UsefulNotes/PlayStation, and German Volume 4, the host for ''Fibbage'', both of its sequels, and ''Fakin' It''. Was TheAnnouncer for the short lived live-action game show.

* AscendedExtra: Went from the green-room organizer to the most recognized host of them all.
* BadBoss: Has killed at least one intern. [[ChainsawGood With a chainsaw]].
* CantHoldHisLiquor: One segment of ''The Ride'' is sponsored by Ye Olde Booze Shoppe. For Cookie, it goes about as well as you'd imagine.
--> '''Cookie:''' "Which of these slang terms for 'Regurgitation' is NOT a good example of 'Onomatopoeia?' Barf, Hurl, Ralph or Upchuck?"
* CatsAreMean: His cats Poopsie and Mayonaise often fall under this.
* DeadpanSnarker
* {{Jerkass}}: In earlier games he'd insult the player's score, give them an embarrassing nickname if they didn't enter one in the box and mock them for not having a social life. He gets better once promoted to host. Sort of.
* TheAnnouncer: In the short lived live action game show.
* TrademarkFavoriteFood: Fortune cookies, in fact there's even a question type in ''2011''.
** Also it's implied in the same game that he loves Pringles.
--> '''Cookie:''' "You know what their slogan says "Once you pop, you can't stop"? It's so true!"

!!!'''Josh "Schmitty" Schmitstinstein'''
-> Now I hope you went before we left, because it's time.
-->-- One of lines he says before a multiplayer game begins in ''Louder! Faster! Funnier!''

-->'''Voiced by:''' Phil Ridarelli

Hosted in ''TV'', part of ''The Ride'', the ''Netshow'', ''Louder! Faster! Funnier!'', ''5th Dementia'', ''Mock 2'', and ''The Lost Gold''. He also acts as TheAnnouncer in ''2011'', the Facebook game and ''2015'', and also serves as the host of ''Quiplash'' and ''Lie Swatter''.
* DemotedToExtra: He went from hosting several games in the series to simply being TheAnnouncer. However, he now hosts ''2015'' 's sister games ''Lie Swatter'' and ''Quiplash''.
* HotBlooded: He tends to be a bit temperamental at times.
* OnlyKnownByTheirNickname
* TheAnnouncer: In ''2011'' and the Facebook Game, and various other games before that.
* TookALevelInJerkass: In ''The Lost Gold'', you flip him off in a Gibberish or an anagram question the first and second times, and your score will suffer.

!!!'''Nate Shapiro'''
-->'''Voiced by:''' Harry Gottlieb

The original host. Starred in ''Volume 1'', the ''Netshow'', the Tiger Electronics Tabletop version and part of ''The Ride''.
* OutOfFocus: Despite being the very first host, he didn't make very many appearances after the first game, due to Harry Gottlieb being more involved with Jackbox Games' sister company Jellyvision. Lampshaded in ''2015'' during the pre-game chatter.
-->''Has anyone seen Nate Shapiro? He hasn't come into the office in, like, 15 years.''

!!!'''Guy Towers'''
-->'''Voiced by:''' Andy Poland

The host of ''Sports'', the ''Sports Netshow'', and part of ''The Ride''.
* BerserkButton: ''The Ride'' reveals that he hates Gibberish Questions.
* LovableJock / JerkJock

!!!'''Buzz Lippman'''
-->'''Voiced by:''' Peter B. Spector

The [[TheScrappy least popular]] of the hosts. Buzz hosted ''Volume 2'' and made [[TheCameo a cameo]] in ''The Ride''.
* ButtMonkey: Was set to host the second episode of ''The Ride'', [[BaitAndSwitch then Cookie opened the trapdoor below him]].
* DemotedToExtra: Just one cameo appearance since he hosted ''2''
* {{Nepotism}}/CoattailRidingRelative: In the Green Room/Pre-game section of ''Volume 2'', phone conversations between the two reveal that Buzz is Nate's cousin.
* TheCameo: In ''The Ride''.
-->'''Voiced by:''' Andy Poland

Was the host of ''Headrush'' before being demoted to Sound Guy. Handles the intercom and technical issues in ''2011'' and the iOS[=/=]Website/{{Facebook}} game.
* DemotedToExtra
* EightiesHair: He's implied to have this.

!!!'''Jack Cake'''
Hosted the British Version of the second volume.

!!!'''Quizmaster Jack'''
The host of the German volumes. Hosted Volume 1, Volume 2, ''Abwärts!'', UsefulNotes/PlayStation, and Volume 4. Voiced by Axel Malzacher in ''Volume 1'' and the latter 4 being voiced by [[TheOtherDarrin Kai Taschner]].

!!!'''Troy Stevens'''
The host of the short-lived live-action game show. Portrayed by Paul Reubens. Currently the only host who has been seen [[spoiler:besides at The Bottom at the end of ''The Ride'', and even then, still the only host seen in full]].

Replaced Cookie as the organizer in ''Movies'', ''Volume 3'', ''TV'' and ''Offine'', and hosted the Netshow.[[note]]One Netshow question asked "Which of these people has never hosted an installment of You Don't Know Jack?" "Cookie" was the correct answer, though it's advertised afterward that he would be hosting Movies. If you chose "Raul", the host angrily told you that ''he's'' Raul.[[/note]]

!!Other Gameshow Staff

The organizer for ''2011''. He's given the task of explaining the rules, setting up the game and occasionally writes questions.

* DelusionsOfEloquence: A severe case. Becomes a bit of a problem in Episode 47 of ''2011'' when a lack of questions forces him to write up his own.
* TheNickNamer: If a player fails to enter their name.
--> '''Donny:''' Player One, you failed to enter your John Hancock. From now on, you're Sisyphus.

A fact finder in 2011 who would occasionally interrupt questions in order to point out mistakes in the questions or Cookie's comments in great detail.

The director in many of the games, most notably ''2011''.

An intern who is a recurring character in ''2011''. He is remarkably dimwitted and frequently annoys Cookie with his idiocy and his habit of losing the questions he's supposed to hand Cookie.
* TheDitz
* ExactlyWhatItSaysOnTheTin: Once wrote a Jack Attack for Episode 47, which could be considered [[http://www.youtube.com/watch?v=17O8i6E5qFI the easiest one created. And the funniest one at that]].

!!Other Characters

!!!'''Old Man'''
Longtime stagehand who ''still'' hasn't died (surprisingly enough), hosted "Old Man's Moldy Memories" in ''Head Rush'' and "Foggy Facts with Old Man" in ''2015'', and is also a recurring character, and is also the spokesperson for Old Man Essence in ''2011'' and Autumn Dusk Feminine Spray in ''Facebook'', [[spoiler:and is supposedly Schmitty's father]]. Also the mayor of Doodle Valley as seen in ''Civic Doodle''.
--> '''"Voiced by"''': Andy Poland
* TheAnnouncer: In ''The Lost Gold''
* AscendedExtra: Goes from a recurring character in YDKJ to co-host of ''Jackbox Party Pack 4'' game ''Civic Doodle''.
* BerserkButton: Swear words. See the EasterEgg example on the Main page.
* DirtyOldMan: In ''[[http://youtu.be/eQFaqZ5Z89E?t=1m54s Volume 3]]''.
* DisproportionateRetribution: Triggering his above BerserkButton habit often results in wishing horrifying and cruel punishments on the player, including calling the air force. Of course, the host is usually sensible enough to just [[VideoGameCrueltyPunishment give a large hit to the player's score and change their name to something insulting]].
* {{Gasshole}}
* [[HisNameReallyIsBarkeep His Name Really Is Old Man.]]
* LukeIAmYourFather: [[spoiler:Played with on ''TV'' if you drop the F-Bomb three times in a gibberish question, and press any key as the game's about to exit to desktop, he'll reveal that he knew Schmitty's mother, which means Old Man is his father.]]
* PyrrhicVictory: Experiences one in ''2011'', and after crapping himself, he cries "Foul!"
* RamblingOldManMonologue: Naturally a fan of these.

!!!'''Chocky the Chipmunk'''
A sociopathic cereal mascot of various cereals including British Chocky Puffs (which contain Squick blood sausage) and Chocky the Chipmunk's Allergy Clusters, which are about as delicious as Grandma's hard diabetes candy ([[FlatJoy "Yay..."]]).

* CatchPhrase: "WOAAAAAAAAAAAAAH!" Also, "pink and tar-ty."
* TheFaceless: Until the Facebook game, where he is depicted on a cereal box in a short advertisement.
* FunnyAnimal
* HeroicComedicSociopath
* {{Mascot}}: For various cereals.

!!!'''Milan The Janitor'''
A character in ''Headrush'' who hosted ''Trash Talking With Milan'', a question type which involves English and Grammar.
--> '''Voiced By"''' Igor Gasowski

* FunnyForeigner

!!!'''The Captain'''
A character in ''The Lost Gold'' who gets cursed after finding Jack Gold. The sign-in host for the game.

* APirate400YearsTooLate
* {{Curse}}: Gets under one in the intro video (for loading the game for the first time), as such he's trapped for eternity being the game's sign-in host that haunts the "Studio" and the player(s) have to accumulate a total of $1,000,000 to free him. In fact, the pirate-themed Impossible Questions in ''The Lost Gold'' are him attempting to speed up the process.

!!!'''Billy O'Brien'''
->''"You nean do I say s***, a**hole or notherf***er?"''
-->-- One of Billy's lines, ''before reading question 9 in episode 4.2 in the iOS version''

Cookie's Ventriloquism puppet and question reader of the "Who's the Dummy?" questions in ''2011'' the first iOS game, [=OUYA=], ''Party'', and ''2015''.

He has trouble pronouncing his Bs, Ps, and Ms, which become Ds, Ts, and Ns respectively. (i.e. bar becomes dar, president becomes tresident, moron becomes noron)

He has a sister named Betty O'Brien and his own ventriloquism puppet named Mikey [=McBride=], which appeared in episode 61 of the 2011 edition for question 8. (However, he said dirates instead of tirates, when he meant pirates, he said dearl instead of tearl, when he meant pearl, and he actually said the correct pronunciation of doubt with a B, rather than doudt.)

* {{Crossover}}: He appears as a monster in ''Monster Seeking Monster'' in the ''Jackbox Party Pack 4''.