She began her career as a teenager with small roles in several of her father's films, and appeared with her brother in the cult favorite Donnie Darko (2001).

[27] Gyllenhaal later achieved recognition in her own right playing her real brother's on-screen sister in the indie cult favorite Donnie Darko (2001).

[28][29] She made her theatrical debut in the Berkeley Repertory Theatre production of Patrick Marber's Closer,[30][31] for which she received favorable reviews.

Gyllenhaal's breakout role was in the black comedy, Secretary (2002), a film about two people who embark on a mutually fulfilling BDSM lifestyle.

[36] The New York Times critic Stephen Holden noted: "The role of Lee, which Maggie Gyllenhaal imbues with a restrained comic delicacy and sweetness, should make her a star.

"[36] Mick LaSalle of the San Francisco Chronicle wrote: "Maggie Gyllenhaal, as the self-destructive secretary, is enigmatic and, at moments, sympathetic.

[45] She later appeared in the unauthorized biography Confessions of a Dangerous Mind (2002), part of an ensemble cast that included Sam Rockwell, Drew Barrymore, George Clooney, and Julia Roberts.

[49] In an interview with The Daily Telegraph, she revealed the reason for accepting the role was "to play somebody who feels confident in herself as a sexy, beautiful woman".

[52] Her next roles were in smaller independent films: Casa de los Babys (2003), is a story about six American women impatiently waiting out their lengthy residency requirements in a South American country before picking up their adoptive babies,[53] and Criminal (2004), a remake of the Argentinian film Nine Queens, with John C. Reilly and Diego Luna.

[60][61] Gyllenhaal's next film role was in the 2005 comedy-drama Happy Endings, in which she played an adventuress singer who seduces a young gay musician (Jason Ritter) as well as his rich father (Tom Arnold).

[63] Following Happy Endings, Gyllenhaal appeared in five films releases in 2006: Trust the Man, Stranger than Fiction, Monster House, World Trade Center, and Sherrybaby.

[66][67] Ethan Alter of Premiere felt that the performances by Gyllenhaal and Duchovny were "much more at ease" and concluded with "that's probably because they're [sic] played these characters many times before".

[79] She appeared in The Dark Knight (2008), the sequel to Batman Begins (2005), in which she replaced Katie Holmes as Assistant District Attorney, Rachel Dawes.

[82] The Dark Knight was a critical and commercial success, setting a new opening weekend box office record for North America.

In a Salon magazine review of the film, Stephanie Zacharek called Gyllenhaal's character "a tough cookie in a Stanwyck-style bias-cut gown" and stated that "the movie feels smarter and more supple when she's on-screen".

[85] IGN film critic Todd Gilchrist wrote, "Gyllenhaal adds real depth and energy to Rachel Dawes".

[86] In addition to film, Gyllenhaal played Yelena Andreevna in the Classic Stage Company's 2009 Off-Broadway production of Anton Chekhov's Uncle Vanya in New York City.

[87] Joe Dziemianowicz of the New York Daily News was unenthusiastic about her performance, writing "Gyllenhaal, who was so dynamic as a druggie in the film Sherrybaby, plays Yelena with a slow-mo saunter and monotonous pasted-on smile that makes it seem as if she's been in Sherry's stash.

[90][91] The film generated broadly mixed reviews,[92] with Owen Gleiberman of Entertainment Weekly describing Gyllenhaal's subplot as "over-the-top".

[104][105] For her next film, Gyllenhaal starred in the biographical romance Hysteria (2011), which focuses on the events that led to the creation of the vibrator during the Victorian era.

[107] In February 2011, Gyllenhaal starred in another Anton Chekhov Off-Broadway production as the character Masha in Austin Pendleton's Three Sisters at the Classic Stage Company.

[108] The play focused on the Prozorov sisters (Gyllenhaal, Jessica Hecht, and Juliet Rylance), who are "unlucky in love, unhappy in the provinces and longing to return to Moscow", as summarized by Bloomberg's Jeremy Gerard.

[114] Also that year, she played Hathfertiti in Matthew Barney and Jonathan Bepler's River of Fundament, loosely based on the 1983 novel Ancient Evenings by Norman Mailer.

[115][116] Gyllenhaal played the lead role as Baroness Nessa Stein, a British-Israeli businesswoman heiress in the BBC political spy thriller television miniseries, The Honourable Woman.

[117][118] The series was well received; Kevin Fallon wrote in the Daily Beast: "Gyllenhaal delivers what might be the most towering, complex, best performance of her career in the miniseries.

[124] Returning to film in 2018, Gyllenhaal starred in The Kindergarten Teacher, a drama in which her character becomes obsessed with a student whom she believes is a child prodigy.

The feature opened to mainly popular reviews; The Daily Telegraph critic gave the film 4 out of 5 stars, and thought Gyllenhaal was well-cast, writing "[her] earnest intensity as an actress, gift for fatigue and slightly holier-than-thou authority are key assets here.

[128] In 2021, Gyllenhaal made her feature directorial debut with the psychological drama The Lost Daughter, which she also produced and adapted from a novella by Elena Ferrante.

[157][158] Gyllenhaal is a supporter of Witness, a non-profit organization that uses video and online technologies to expose human rights violations.

It has become such a politicized issue and so I will make every effort to elect officials who believe as strongly as I do that all women [...] have access to quality health care and information.