The streaming service announced the casting news on Friday.
Now shooting in Los Angeles, the movie co-stars Clark Gregg, Nico Hiraga, Alycia Pascual-Peña, Sydney Park, Anjelika Washington, Josephine Langford, Joshua Darnell Walker, Josie Totah, Sabrina Haskett, Charlie Hall, Hadley Robinson, Lauren Tsai, Patrick Schwarzenegger and Ike Barinholtz
After scribe Tamara Chestna wrote the screenplay, based on Jennifer Mathieu's book about a young girl from a small town who starts a feminist revolution at her high school.
Saturday Night Live and Parks and Recreation alum Poehler previously helmed and starred in the comedy Wine Country for Netflix.
Harden's credits include the Fifty Shades franchise, Mystic River and Pollock.