Born and raised in Los Angeles to parents who both worked in the entertainment industry, Stewart first gained notice at age 12 for her role as the daughter of Jodie Foster's character in David Fincher's thriller Panic Room (2002).

She was acclaimed for her performance in Olivier Assayas' drama film Clouds of Sils Maria (2014), which won her the César Award for Best Supporting Actress.

Stewart returned to mainstream Hollywood with leading roles in the action film Charlie's Angels (2019) and the romantic comedy Happiest Season (2020).

Her portrayal of Diana, Princess of Wales in Pablo Larraín's biographical drama Spencer (2021) earned her a nomination for the Academy Award for Best Actress.

Stewart also played the tomboy, diabetic daughter of a divorced mother (Jodie Foster) in the thriller film Panic Room (2002), directed by David Fincher.

[13] Following the success of Panic Room, Stewart was cast in another thriller, Cold Creek Manor (2003), playing the daughter of Dennis Quaid and Sharon Stone's characters and receiving a Young Artist Award nomination for her performance.

[14] At age fourteen, Stewart had her first starring role in the children's action-comedy Catch That Kid (2004), opposite Max Thieriot and Corbin Bleu.

Stewart, aged thirteen at the time of filming, played Melinda Sordino, a high school freshman who nearly stops speaking after being raped.

"[15] Stewart appeared in the fantasy-adventure film Zathura: A Space Adventure (2005), playing the role of Lisa Budwing, the irresponsible older sister of two little boys.

Stewart appeared as teenager Lucy Hardwicke in In the Land of Women (2007), a romantic drama starring Meg Ryan and Adam Brody.

That same year, Stewart had a small role in the Sean Penn-directed adaptation Into the Wild, portraying Tracy—a teenage singer who has a crush on young adventurer Christopher McCandless (played by Emile Hirsch).

While Stephanie Zacharek of Salon.com considered her work a "sturdy, sensitive performance", and the Chicago Tribune's Michael Phillips noted that she did "vividly well with a sketch of a role", Variety critic Dennis Harvey said, "It's unclear whether Stewart means to be playing hippie-chick Tracy as vapid, or whether it just comes off that way.

[21] Critic Bill Goodykoontz from The Arizona Republic said that Stewart "really shines.... She excels at both aspects of the performance, giving Georgia a strength that defies any sort of pity one might feel for her, without letting us forget her vulnerability".

[22] On November 16, 2007, Summit Entertainment announced that Stewart would play main character Bella Swan in the romantic fantasy film Twilight, based on Stephenie Meyer's novel of the same name.

[26] Owen Gleiberman of Entertainment Weekly described her as "the ideal casting choice" and praised her for conveying "Bella's detachment, as well as her need to bust through it", while Claudia Puig of USA Today criticized her acting for being "wooden" and lacking variety in her "blank" facial expressions.

Jordan Mintzer from Variety called Stewart "the heart and soul of the film" and praised her for giving "both weight and depth to dialogue...she makes Bella's psychological wounds seem like the real deal.

That same year, Stewart portrayed rock star Joan Jett in The Runaways, a biographical film of the titular band from writer-director Floria Sigismondi.

[56] While it generated mixed reviews from critics, Stewart's performance as a young soldier stationed at Guantanamo Bay detention camp received praise.

"[64] Peter Debruge of Variety praised Stewart's "spontaneous, agitated energy that makes her the most compellingly watchable American actress of her generation.

"[65] Robbie Collin of The Daily Telegraph described her portrayal as "sharp and subtle, knowable and then suddenly distant" and highlighted the "brilliant lightness of touch" in her approach to the film's twist.

[62] Peter Travers of Rolling Stone called her "wonderfully vibrant and contentious" and said: "Even when Still Alice sometimes slips into sentiment, Moore and Stewart are funny, fierce and glorious.

[69] Stewart appeared in Tim Blake Nelson's Anesthesia, an indie drama about a group of New Yorkers, which was released on January 8, 2016, by IFC Films.

[75] Stewart also reunited with Clouds of Sils Maria director Olivier Assayas to headline his film Personal Shopper, a ghost story that takes place in the fashion industry.

[79] In the same year, Stewart was also an honoree at Elle's Women in Hollywood Awards alongside Amy Adams, Felicity Jones, Anna Kendrick, Aja Naomi King, Helen Mirren, and Lupita Nyong'o.

[84] That same year, Stewart hosted Saturday Night Live for the first time with musical guest Alessia Cara[85] and was invited to join the Academy of Motion Picture Arts and Sciences.

[101][102] Stewart wrote and directed a short film titled Crickets, as part of the anthology series Homemade which follows stories from 18 filmmakers from around the world during the COVID-19 pandemic isolation.

[103] Stewart later starred opposite Mackenzie Davis in Happiest Season, an LGBT holiday romance film directed by Clea DuVall, which was released on November 25, 2020.

[107] Describing Diana as someone who "sticks out as a sparkly house on fire", Stewart said she "felt more free and alive and able to move" in the role than she did in any of her previous projects.

[109][110] Critics lauded Stewart's portrayal of Diana, with Jonathan Romney of Screen Daily describing it as "brittle, tender, sometimes playful and not a little uncanny" and Kyle Buchanan of The New York Times deeming her casting "a meta stroke of genius".

[141] In 2016, she participated in building a school in Nicaragua through the nonprofit buildOn, with the goal being to give children the opportunity to become educated in a safe space and to break the cycle of poverty and illiteracy.