Played by Glenn Howerton
The Main Character, Jack is a former Harvard Professor who was thrown out of academia for unknown reasons. He "is" an AP Biology teacher who doesn't care for biology and wants to be reinstated at Harvard as a philosopher.
- Apathetic Teacher: He does not care at all for the future of his students.
- Apple for Teacher: He constantly eats apples, but throws them away after only one bite.
- Berserk Button: He has many.
- Whenever someone tries to make him teach biology.
- Whenever someone mentions Miles Leonard's accomplishments and accolades.
- Being denied his "right" to eat Sun Chips during class.
- Whenever his students try to learn biology.
- Whenever his students even mention biology or try to read their textbooks.
- He just really hates children and teenagers overall, and does not like having to be around them.
- He really hates the saxophone.
- He also hates rap music.
- Brilliant, but Lazy: He actually does know biology, but won't teach it. Matter of fact, he's very much a genius who's nearly impossible to deceive.
- The Bully: To his students. He makes them throw out their biology textbooks, insults them on a daily basis and forces them to work hard to make him rich and popular with women.
- Catchphrase: "Alright everybody, start to shut up!"
- Control Freak: Being a Lazy Bum, he forces his students to build up his future and career instead of doing it himself.
- Determinator: Jack refuses to ever teach his students any AP Biology despite the fact that A) he's an expert on the subject and can profess it with relative ease and B) his students are always rebelling and trying to get him fired as retaliation for forcing them to skip learning biology and do ridiculous tasks about helping him gain money and women. He will go through any means to avoid teaching them any biology no matter how badly he suffers doing so.
- Evil Genius: Whenever his students lie or try to get rid of him, Jack will always find out.
- Green-Eyed Monster: Towards Miles Leonard for becoming the head of Philosophy at Stanford, a position that Jack feels should have went to him.
- Hoist by His Own Petard: Jack setting up Miles through catfish with his students in the pilot episode is the one revenge mission to ruin Miles' career that succeeded so well not only did Stanford fire Miles, but even Jack can't replace Miles as head of Philosophy in Stanford because Miles recommended him.
- Jerkass: He is very anti-social, misanthropic and treats his students like toilet paper, routinely yells at them to shut up, not write down what he says and bullies/insults them for petty reasons.
- Karma Houdini: He gets away with whatever he does, mainly because of Ralph's incompetence.
- Narcissist: Jack thinks he's smarter than anyone else in Toledo. In the pilot episode he says that he's smarter than all his students combined.
- The Pirates Who Don't Do Anything: He's an AP Biology teacher who never teaches biology, matter of fact he wants his students to stay uneducated about science!
- Seven Deadly Sins:
- Wrath: His "favorite" sin. He's always taking out his frustration and anger on both Ralph and his students. By the way, what did he do the first time we see him on-screen? Rage-drive through the school sign and scare off an angry bystander he almost ran over with a crowbar!
- Pride: He considers himself smarter than everyone, especially his students.
- Lust: He wants to have hard sex with his ex-high school girlfriend and pursue other Californian women. Many times he even draws crude stick figures of him having sex with nude women on the chalkboard for his students to see.
- Gluttony: Always, ALWAYS eating in the classroom.
- Greed: Refuses to pay for the lucrative school sign he demolished in the pilot episode, coldly forces Ralph to just repair the sign himself using funds from the school's tight budget.
- Sloth: Never teaches his students ANY biology. Period.
- Envy: He seriously envies his nemesis Miles Leonard for stealing his job as a philosopher.
- The Snack Is More Interesting: He's always eating, never teaching in the classroom.
- Trademark Favorite Food: Of the many foods he routinely eats, he appears to like Sun Chips the best.
- Villain Protagonist: And he's well-aware he fits this trope.
- Voice Changeling: He pulls this off on his students to insult them further in "Walleye".
Played by Patton Oswalt
The pushover principal of the school.
- Adults Are Useless: He doesn't ever take any disciplinary action (or at least not successfully) against Jack for the way he treats his students. Ironically, it's been proven there are other competent biology professors in the area lined up to take Jack's job. Ralph almost gets put on disciplinary action for his incompetence in "Teacher Jail".
- Butt-Monkey: He constantly suffers getting taken advantage of by Jack and the other teachers for his generosity and pushover personality.
- Extreme Doormat: Always lets other people, especially Jack, walk all over him.
- Fat Idiot: He's an obese and incompetent school principal.
- Fat and Skinny: The fat guy to Jack's skinny.
- Henpecked Husband: Ralph isn't really fond of his socially awkward wife, but doesn't have the courage to stand up to her as he prefers running away to go sleep at Jack's place than spend the night with her.
- Lovable Coward: He often lacks the courage to stand up to anyone, including his own employees such as in "Burning Miles" when he tried to make cuts to the school's budget to repair the school sign Jack broke and every teacher he went to demanded they get an unnecessary luxury such as a parachute or a karaoke machine. And of course Ralph gave in to their petty demands.
Played by Lyric Lewis
A History Teacher
Played by Mary Sohn
An Art Teacher
- Narcissist: She's very vain about her appearance and enjoys making her students create seductive drawings of her.
Played by Jean Villepique
A Home Economics teacher
Played by Paula Pell
Durban's eccentric secretary
- Butch Lesbian: As revealed in Season 2
Played by Charlie McCrackinThe P.E. coach.
- The Bully: He bullied his own boss Ralph into giving him a parachute in "Burning Miles".
- Drill Sergeant Nasty: As PE coach, he deliberately tires out all the boys to make sure they don't have the energy to vandalize the school.
- Fat Bastard: He's despicable, loud, rude and very fat in spite of being a health teacher himself.
- Jerkass: He's always bossing other people around (even if it's Principal Durbin).
- No Indoor Voice: He's prone to yelling.
Played by Aparna BrielleAn Indian-American student who vocally opposes Jack's laziness and hostility towards the class.
- Alliterative Name: Jack finds her name amusing.
- Book Worm: Thoroughly treasures her biology textbook above family and friends.
- Catchphrase: "I speak on behalf..."
- Hoist by His Own Petard: Many schemes she cooks up to get rid of Jack often backfire on her and the entire AP Bio class, such as if Jack were to be framed for negligence and a student got hurt, then Jack would just go on paid vacation thanks to the corrupt teachers union representative.
- Ice Queen: She is the most rebellious towards Jack, and has a cold hearted personality that not even her own mother can stand to be with her.
- The Starscream: Is always scheming to get Jack fired, but never succeeds.
Played by Nick PeineA smug, insufferable nerd in AP Bio that has a secretly power-hungry side and is frequently tormented by Jack who believes that bullying him is the only way of keep his obnoxious personality in check.
- Butt-Monkey: Marcus tends to suffer the most abuse from Jack (along with other staff members) due his grating voice, smug and condescending know-it-all demeanor and the way he sass backs Jack any chance he gets he gets.
- Insufferable Genius: Marcus is the arrogant know-it-all that even the equally insufferable Miles is instantly annoyed by him when they first meet.
- Jerk with a Heart of Gold: While Marcus's traits can infuriate adults, he is still rational and does generally get along with other classmates to the point that even calling Sarika his best friend when she becomes socially insecure and the other students try to cheer her up. He also believes in not taking advantage of Jack in "Burning Miles" when Jack is clearly more pitiful than usual.
- Sitcom Arch-Nemesis: While it would be a stretch to say that Jack likes any of his students, he seems to especially hate Marcus, due to his grating voice and tendency to (rightfully) call him out on his behavior.
- Smug Snake: Marcus has shades of this when interacting with Jack who's just as obnoxious. While he's generally too powerless to flaunt it, "Overachieving Virgins" really highlights what a tyrannical and selfish jerk he can be when he bullies the rather timid Victor.
- Student Council President: Marcus is the student council president, and a rather controlling one at that. His clash with Jack over vending machine contents results in Jack revealing that his parents had rigged the school election to allow him to win, resulting in him losing his title in the same episode in which it is learned that he held it.
Played by Allisyn Ashley ArmThe glasses girl in Jack's AP Bio class and a quiet, reserved but sometimes unbalanced cloudcuckoolander.
- Cloudcuckoolander: Is socially eccentric and unpredictable.
- Hollywood Autism: She behaves much like an autistic person.
- Likes Older Men: She has a crush on Miles Leonard and would often use a Miles mission to get close to him.
- Nerd Glasses: She's a socially awkward nerd who wears glasses.
- The Starscream: In "8 Pigs and a Rat", she tried ratting out Jack to Durbin about cancelling the fetal pig dissection. Granted, in the pilot episode Jack DID force Heather at academic gunpoint to prostitute herself out to Miles Leonard online with (false) promises of sex.
Played by Eddie LeavyBasically the same person as Ralph Durbin but as a student, not a principal.
- The Big Guy: He's the biggest and strongest of the students, and Jack has him steal a statue from a church.
- Book Dumb: He complains that his GPA is below average.
- Butt-Monkey: He gets regularly bullied by Jack, but does nothing since he desperately wants an A grade in AP Bio and the recommendation letters for college applications as a means of breaking his high school history as a mediocre student.
- Gentle Giant: He's the biggest student in AP Bio and while he has an intimidating size, often gets along with the other kids. He's also rather quiet and reserved even if his expressive T-shirts emphasize negativity.
Played by Spencer Moore II
Played by Jacob McCarthyA quiet, reserved kid in AP Bio who spends his time there drawing Satanic rituals into a sketchbook. Jack calls him "Prince of Darkness".
- Apocalypse Anarchy: He enjoys reading and drawing about anarchy. He was first seen reading the book "Anarchy in Action" by Colin Ward.
- Chuck Cunningham Syndrome: He disappears without a given reason from Season 2. His desk was empty in the Season 2 opener. It is unconfirmed if he'll return in Season 3.
- Hollywood Satanism: He is into a cult that worships Satan and the bringing of the Apocalypse.
- Mad Artist: He likes to draw Satanic symbols and figures into his sketchbook from the perspective of being a demon.
- Wild Card: He's not exactly on Jack's side, but not against Jack either like the other AP Bio kids. Matter of fact, he gets amused by Jack's rebellious attitude towards the institution of learning to which he utters "Cool".
Outside the School
- Hero Antagonist
- Nice Guy: In spite of Jack's burning hatred for him, he's actually a very compassionate person. Matter of fact, he vigorously tried to help boost Jack's career and get him a better paying job.
- Put on a Bus: He is gone from Season 2, implying that Jack finally got revenge on him through a mission.