Stewart's first starring role was at age 14 in the children's action-comedy Catch That Kid (2004), opposite Max Thieriot and Corbin Bleu.That year Stewart also played the role of Lila in the thriller, Undertow (2004).She is a script supervisor and has also directed a film, the 2012 prison drama K-11.As she grew up with a family who worked behind the camera, Stewart thought she would become a screenwriter/director, but never considered being an actor.The film, as well as Stewart's performance, received mixed reviews.
The next year, she played the character Maya in Fierce People (2006), directed by Griffin Dunne.
For her portrayal of Tracy – a teenage singer who has a crush on young adventurer Christopher Mc Candless (played by Emile Hirsch) – Stewart received mixed reviews.
While considered her work a "sturdy, sensitive performance", and the Chicago Tribune noted that she did "vividly well with a sketch of a role", Variety Critic Bill Goodykoontz from The Arizona Republic said that Stewart "really shines....
She received widespread recognition in 2008 for playing Bella Swan in The Twilight Saga film series (2008–12), which grossed over .3 billion worldwide.
Stewart has appeared in a wide variety of films, including Adventureland (2009), The Runaways (2010), Snow White and the Huntsman (2012), On the Road (2012), Camp X-Ray (2014), Still Alice (2014) and Equals (2015).