Allen Gregory De Longpre (Jonah Hill), one of the most pretentious seven-year-olds of our time, is forced to face his greatest challenge – attending elementary school. His mature ways make it hard for him to assimilate, and his struggle to adjust is not limited to his classmates. As Allen Gregory makes his rounds with the faculty, his first meeting with his much-older principal (guest voice Renée Taylor) takes a special turn.
After discovering that his rival classmate, Joel Zadak (guest voice Jake Johnson of NEW GIRL), has a girlfriend, Allen Gregory tries to raise his social quota by sparking a sex tape scandal with Principal Gottlieb. To help Allen Gregory’s adopted sister, Julie (Joy Osmanski), appear “normal,” Richard and Jeremy hire cool-looking kids to hang out with her.
When Allen Gregory’s doting – and comically malevolent – dad, Richard (French Stewart), helps plan Allen Gregory’s first school dance, tension occurs after popular stud Joel Zadak invites Allen Gregory’s trusty friend, Patrick (Cristina Pucelli), and not Allen Gregory. Meanwhile, jealousy sparks when Richard’s life partner, Jeremy (Nat Faxon), gets a job as a D.J. at Kirby’s Roller Bowl.
When Joel Zadak (guest voice Jake Johnson) stays home from school because he’s sick, the always presumptuous Allen Gregory (Jonah Hill) steps in to help his popular “friend” by keeping tabs on the clique. As Allen Gregory gains some ground with the exclusive group, Zadak loses more than his friends. Meanwhile, Richard (French Stewart) hits the boardroom at his father’s company.
Allen Gregory’s teacher, Gina (guest voice Leslie Mann), seeks to teach him a lesson on racism after he mistakes his Hispanic schoolmate, Guillermo (Jonah Hill), for a janitor. Much to Gina’s dismay, Allen Gregory produces a play to depict his point of view of the incident. Meanwhile, Richard hires Jeremy as his new maid.
Allen Gregory (Jonah Hill) enlists the help of a friend to find his biological mother. Though Allen Gregory initially dreams of his mother and father falling in love and starting a life together, he soon realizes that this new “family” is not all it’s cracked up to be.
The persistent and pompous Allen Gregory bribes Principal Gottlieb into a romantic situation that he hopes will bring them closer together. Meanwhile, Richard uses Julie to compete with his frenemy's adopted child.