Hailee Steinfeld as 17-year-old Nadine Franklin[4] Haley Lu Richardson as Krista, Nadine’s best friend[5] Blake Jenner as Darian, Nadine's older brother[6] Woody Harrelson as Mr. Bruner, a high school teacher[7] Kyra Sedgwick as Mona, Nadine's mother[7] Hayden Szeto as Erwin Kim, Nadine's awkward admirer[6] Eric Keenleyside as Tom Laine MacNeil as TCBY Yogurt Girl Katie Stuart as Jeannie Alexander Calvert as Nick Mossman Meredith Monroe as Greer, Mr Bruner wife