2020–present: Breakthrough and expansion
In January 2019, it was announced Fennell would produce, write and direct the comedy thriller film Promising Young Woman, starring Carey Mulligan. Production began in March 2019. Fennell was seven months pregnant during the 23-day shoot. About her initial concept for the film, Fennell stated that she imagined, "...a scene of a drunk girl on a bed, being undressed, saying "What are you doing?" incredibly drunkenly and then sitting up sober. From that moment, I knew roughly what it was going to be." The movie premiered at the 2020 Sundance Film Festival to critical acclaim with, as of August 2023, a 90% score on Rotten Tomatoes, and a critical consensus of: "A boldly provocative, timely thriller, Promising Young Woman is an auspicious feature debut for writer-director Emerald Fennell -- and a career highlight for Carey Mulligan."
Even so, the film was notable for its controversial ending, to which Fennell stated, "The original ending was deemed too bleak, and normally, I wouldn't care about being too bleak. But the point was made to me [by the studio]. There comes a point where something can be so enraging to an audience that people won't want to watch it." Fennell made a brief uncredited appearance in the film as the host of a 'blowjob lip' make-up tutorial video. She also produced the film with, amongst others, Margot Robbie and her LuckyChap Entertainment production company. The film went on to earn five Academy Award nominations, including Best Picture, Best Director, and Best Original Screenplay for Fennell. She became one of only seven women, and the first British woman, to earn a nomination in the directing category. As well, Fennell's directing nomination alongside that of Chloé Zhao marked the first instance of two women earning directing nominations in the same year. For the film, she received Best Original Screenplay awards at the Critics Choice Awards, the Writers Guild of America Awards, and the Academy Awards.
In January 2020, Andrew Lloyd Webber announced he would collaborate with Fennell on the musical Cinderella, which opened in London in August 2021. The West End production received generally positive reviews from critics. It made the transfer to Broadway in 2023, titled Bad Cinderella, with Fennell's original book adapted by playwright Alexis Scheer. Naveen Kumar for Variety criticised the revised book, writing, "[it's] an illogical head-scratcher, despite being based on a story most everyone knows". The show closed in June 2023.
On 22 March 2021, Fennell was attached to write a Zatanna film for Warner Brothers, set in the DC Extended Universe. On 18 May 2021, Mark Millar revealed that Fennell had written the latest screenplay of the film adaptation of his comic Nemesis. In 2023, Fennell told The New Yorker Radio Hour that she is no longer attached to either film. About Zatanna, Fennell later confessed, "It was a script reflective of a woman in the middle of a nervous breakdown... it was maybe too far away from the (superhero) genre... It was really dark." In July 2022, Cuban-Spanish actress Ana de Armas stated in an interview with Elle that Fennell was hired to contribute to the script of the John Wick spin-off film Ballerina as one of its writers. The film was released in June 2025.
In 2023, Fennell wrote, produced, and directed her second feature film, Saltburn, a black comedy and psychological thriller starring Barry Keoghan, Jacob Elordi, Rosamund Pike, Richard E. Grant, Alison Oliver and Archie Madekwe. The film premiered at the 50th Telluride Film Festival. It received generally positive reviews, with critics praising the performances and cinematography while criticising its ending. On Rotten Tomatoes, the film's critical consensus states, "Emerald Fennell's candy-coated and incisive Saltburn is a debauched jolt to the senses that will be invigorating for most." The film was shot using a 1.33:1 aspect ratio, usually used in silent films. About her inspiration for Saltburn, Fennell stated, "So much of this film, and so much of everything I make, is me trying to come to terms with what an embarrassing person I am [and] what embarrassing people we all are." In producing Saltburn, Fennell specified, "All the editing was in Soho, London, and then we did sound editorial at Cinphonic, ADR at Goldcrest, the score was done at Air Studios and the re-recording mix in Dolby Atmos was at Pinewood. I love the whole post-process, especially the editing." That same year, Fennell also played the role of Midge in Greta Gerwig's fantasy comedy film Barbie.
In July 2024, she announced that her next film would be an adaptation of Emily Brontë's novel Wuthering Heights. Later that year, it was announced that Margot Robbie and Jacob Elordi would be starring as Cathy and Heathcliff respectively. Fennell asked Elordi to play Heathcliff after seeing him on the set of Saltburn one day, as he "looked exactly like the illustration of Heathcliff in the first book that I read." The casting was widely criticised online due to Robbie being cast as a teenage protagonist and Elordi playing a role described as "dark-skinned" in the original novel. In talking about her goals for the film, Fennell stated, "I wanted to make something that made me feel like I felt when I first read it, which means that it's an emotional response to something. It's, like, primal, sexual." Wuthering Heights was released in February 2026 to mixed reviews.
