Produced by John Hughes, a 16-year old student teams up with a gym teacher in order to save the school from being bought by the government.
- Denis Francies (Tom Holland) - the main protagonist, 16-year old high school, whose main focus is about his life, his friends, his parents and relationships, he seeks to save the school from being bought, in the end, He ends up saving the school from the hands of fools.
- Gideon Jaspar (Chris Pratt) - the deuteragonist, Denis's gym teacher and father figure, as he and Denis seek to find a way to save the school from being bought, his main focus is his relationship with his girlfriend, Bianca, in the end, has a relationship with Bianca in France.
- Lucy Graves (Dove Cameron) - the tritagonist, Denis's childhood best friend, who has hidden feelings for him, and helps save the school, in the end, dances with Denis in the Homecoming party.
- Principal Horatio Hancock (Jeff Daniels) - the principal of the school, who is forced to sell the school, in the end, is dancing with the school staff in celebration.
- Tobias Francies (Steve Carrell) - Denis's overworking father, who barely pays attention to him, in the end, is seen making things right with his son,
- Marcie Francies (Elizabeth Mitchell) - Denis's mother, who is always talking to him, about his life at school, and how his father would still love him, in the end, is seen talking to Lucy about further relationships.
- Bianca Ferris (Bryce Dallas Howard) - Gideon's girlfriend, who is supporting him to save the school, but has problems with him working, in the end, is in a relationship with Gideon in France by swimming with him in the resort pool.
- Agent Vladimir Duvall (Ben Mendelsohn) - the film's main antagonist, the owner of the government who seeks to buy the school for Bingo for old people, in the end, it is revealed to be a ruse just to steal a mob treasure buried within the lower chambers of the school, he was shot to death by Tobias who was saving his son.
- Cameron Wilkinson (Clark Gregg) - Denis's school teacher, who is always happy to help, in the end, becomes Vice Principle.
- Harvey Quint (Jacob Batalon) - Denis's other childhood best friend, who helps support the school, in the end, He reveals Duvall's true intentions when he recognized him in an article on Mafia Treasure.
- Kirkland Vance (Abraham Attah) - one of Denis's classmates and friends, in the end, calls the cops on Vladimir's agents who hold them captive for 12 hours.
- Britney Malnew (Tiffany Espensen) - one of Denis's classmates and friends, in the end, has a relationship with Harvey.
- Neil Brand (Tony Revolori) - Denis's rival at school, who occasionally makes fun of him, but is always helpful when needed, he doesn't care if the school gets closed and would be happy if it does become a Bingo Parlor, in the end, realizes the truth and helps him stop Duvall.
- Jordon Ralfe (Michael Barbieri) - Neil's buddy, who also hates the school, in the end, it is revealed he was a spy for Vladimir using Neil to get to the lower levels of the schools, he was defeated by Neil.
- Eva Wendel (Isabella Amara) - Neil's girlfriend who is rivals with Lucy, in the end, She was using Neil to get to the treasure for her uncle Duvall, she was arrested by the cops.