Mitchell was born in Mississauga, Ontario. She is an actress known to television audiences as Emily Fields on Freeform's Pretty Little Liars. In 2011, she received a Young Hollywood Award for her work on the hit show. She'd go on to star in Lifetime's You along with Penn Badgley.
She began her career as a model, participating in a notable campaign for American Eagle Outfitters.
In 2010, she appeared in a Disney XD series called Aaron Stone.
She was born to Precious and Mark Mitchell and raised alongside a younger brother named Sean. Her father is of Scottish and Irish descent and her mother, who is Filipina, is from the province of Pampanga. She has been in a relationship with Matte Babel. She and Babel welcomed a daughter named Atlas in 2019. She was previously romantically tied to Carlos PenaVega. In February 2022, she announced that she is expecting her second child. She welcomed her second daughter in June 2022.