Blunt made her acting debut in a 2001 stage production of The Royal Family and portrayed Catherine Howard in the television miniseries Henry VIII (2003).

She has since starred in the sequels Mary Poppins Returns (2018) and A Quiet Place Part II (2021), the fantasy adventure Jungle Cruise (2021), and the revisionist Western television miniseries The English (2022).

[17] Critic Tom Keatinge hailed the production, writing that "Peter Hall's direction and Anthony Ward's tremendous set combine with all this to make The Royal Family a terrific night's entertainment", and that "it provides a vehicle for acting of the finest quality, with strong performances from the whole ensemble".

[1][20] In 2003, Blunt made her screen debut in the British television drama Boudica, about the life of the ancient Celtic warrior-queen who fought the Romans.

[20] In 2004, Blunt made her theatrical film debut in Paweł Pawlikowski's critically acclaimed independent British drama My Summer of Love, about an infatuation between two young women from different socioeconomic backgrounds in the English countryside.

"[21][16] Co-starring as Tamsin, she received considerable attention for her performance,[20] garnering critical praise,[22] with David Ansen of Newsweek writing: "Press and Blunt are major discoveries ... they conjure up the role-playing raptures of youth with perfect poetic pitch".

[24] She credited her experience making the film as having an impact on her career choices, stating that it was "such a foray into the great unknown ....[like] putting your feet to the fire" and she "loved that feeling of terror and excitement" and "looked for it ever since.

[20] In 2008, Blunt appeared in Sunshine Cleaning in the role of Norah Lorkowski, an underachiever who starts a crime-scene clean-up business with her sister Rose (Amy Adams).

Peter Travers of Rolling Stone magazine commented "This funny and touching movie depends on two can-do actresses to scrub past the biohazard of noxious clichés that threaten to intrude.

"[32] A. O. Scott of The New York Times agreed, stating "Amy Adams and Emily Blunt [...] attack their roles with vivacity and dedication..."[33] She then starred in The Great Buck Howard as Valerie Brennan, which premiered at the same festival.

Owen Gleiberman of Entertainment Weekly concluded that "Director Jean-Marc Vallée's images have a creamy stateliness, but this is no gilded princess fantasy – it's the story of a budding ruler who learns to control her surroundings, and Blunt makes that journey at once authentic and relevant.

[41][42] Blunt was offered the role of Natasha Romanoff / Black Widow for Iron Man 2 (2010), but she was contractually obligated by 20th Century Fox to join the Jack Black-led comedy film Gulliver's Travels after the studio exercised an option it had for her when she signed on for The Devil Wears Prada.

She played a financial adviser who recruits a fisheries expert to help realise a sheikh's vision of bringing the sport of fly fishing to the Yemen desert, resulting in a spiritual journey for both in the process.

The film earned positive reviews, with Elizabeth Weitzman of the New York Daily News remarking that "Blunt has never been more relaxed, and she and Segel have a believably warm chemistry.

[56] Blunt played Sergeant Rita Vrataski, a Special Forces warrior tasked with training a public relations officer to defeat invading extraterrestrials.

Blunt trained three months for her role, "focusing on everything from weights to sprints to yoga, aerial wire work and gymnastics", and studying Krav Maga.

[60] Blunt then played the role of the Baker's Wife in The Walt Disney Company's film adaptation of Stephen Sondheim's musical Into the Woods, directed by Rob Marshall and featuring an ensemble cast.

Richard Corliss of Time remarked that "When Blunt is onscreen, these woods are alive with the magic of a fractured fairy tale..."[65] She was nominated for her second Golden Globe Award for Best Actress – Motion Picture Comedy or Musical for her performance.

Writing for Rolling Stone, Peter Travers remarked that "the movie gives away the game faster than the novel", but credited Blunt for "playing the hell out of [her character] and adding a touch of welcome empathy.

[75] The script was originally written by Scott Beck and Bryan Woods, who began writing it in January 2016 based on a concept they conceived in college,[76] and they wanted Blunt for the role of the mother.

"[78] Blunt initially did not want to be cast, but after reading Krasinski's draft on a plane flight she felt she needed to do it as the story "represented some of my deepest fears – of not being able to protect my children.

[79][78] A Quiet Place served as the opening night film at the 2018 South by Southwest film festival, where it received critical acclaim;[80][81] Eric Kohn of IndieWire lauded the cast for "contribut[ing] credible intensity to their scenes with a degree of sophistication rare for this type of material", while Laura Prudom of IGN remarked that, "Blunt, in particular, is put through the wringer in ways that would seem almost farcical, if she didn't play them with such compelling conviction.

[84] Owen Gleiberman of Variety found Blunt to be "practically perfect in every way" and added that she "inhabits Mary Poppins' snappishly entrancing spirit, and in the musical numbers she generates her own spit-spot radiance".

[98] Jeannette Catsoulis of The New York Times disliked the picture and opined that "not even Emily Blunt, doing her best Katharine Hepburn impression, can keep this leaky boat ride afloat".

[105] Nolan said that he thought about "running away" from the character while writing the script as she was "terrifying", but Blunt humanised her and surprised him in how she embraced her negative qualities; "No vanity, no fear of humiliation, no wanting to control the way she would appear".

[111][112] Writing for Empire, Dan Jolin said that Blunt "busts out of the supportive/suffering wife archetype as the alcoholic but sharp-witted Kitty Oppenheimer" and delivers "one of the film's most rousing scenes in an intense verbal duel with bullish lawyer Roger Robb",[113] and Tomris Laffly of The Wrap called her performance "subtly scene-stealing".

[134] The Guardian observed her ability to not be pigeonholed into a type of role, and wrote that she "specialises in a sort of calculated understatement", praising her "insight into what makes characters tick and her facility for accents".

[27] The New York Times regarded Blunt as having a "taste for the offbeat and a fetching lack of vanity when it comes to playing disagreeable women" and noted her "adventurous spirit" as a performer.

[132] Catherine Shoard of The Guardian named her "the biggest British female movie star of her generation", comparing her to Keira Knightley, Carey Mulligan, Rachel Weisz, and Kate Winslet.

[149] According to the review aggregator site Rotten Tomatoes and the box office site Box Office Mojo, Blunt's most critically acclaimed and commercially successful films include My Summer of Love (2004), The Devil Wears Prada (2006), Sunshine Cleaning (2008), Your Sister's Sister (2011), Looper (2012), Edge of Tomorrow (2014), Into the Woods (2014), Sicario (2015), The Girl on the Train (2016), A Quiet Place (2018), Mary Poppins Returns (2018), A Quiet Place Part II (2021), and Oppenheimer (2023).