Acting In early 2015, Alwyn was cast in the lead role of Taiwanese director
Ang Lee's 2016 war drama film, ''
Billy Lynn's Long Halftime Walk'', which is a film adaptation of
the 2012 novel of the same name by American writer
Ben Fountain. Lee stated that he selected Alwyn because of his "ability to communicate the book's paradox of war with just his facial expressions". Alwyn came to the United States for the first time after passing the film's auditions. He stated that he didn't "exactly fit" the casting requirements of the role, which were "a 19-year-old U.S. Army grunt"; Alwyn said he had long blond hair and was "a lot skinnier" when he auditioned. In reviews of the film, critics praised Alwyn's performance for its naturalism. Alwyn appeared in a number of 2018 films. He played a supporting role as the British nobleman
Samuel Masham in the
period black comedy film
The Favourite, directed by Greek filmmaker
Yorgos Lanthimos. The film garnered 10 nominations at the
91st Academy Awards. Lauren McCarthy of
W magazine praised Alwyn's physical humour and silly acting style in the film, in contrast to his "
boy-next-door-meets-movie-star-hearthrob looks". He played a supporting role in
Chris Weitz's historical drama
Operation Finale, and a minor role in
Joel Edgerton's
Boy Erased—a biographical drama film based on
a 2016 memoir by American LGBT+ activist
Garrard Conley. Alwyn won the
Trophée Chopard alongside Australian actress
Elizabeth Debicki at the
2018 Cannes Film Festival. In 2019, Alwyn played a slave owner in
Harriet, a biographical drama about
Harriet Tubman. He appeared as
Bob Cratchit in the dark fantasy television miniseries
A Christmas Carol, based on
Charles Dickens'
1843 novella of the same name. In 2021, he had a minor role in drama film
The Souvenir Part II, and played a 1960s industrialist in the film adaptation of
Jojo Moyes' 2008 romantic novel,
The Last Letter from Your Lover. In 2022, Alwyn starred in the drama series
Conversations with Friends—a
Hulu adaptation of
the 2017 novel of the same name by Irish author
Sally Rooney. Alwyn was paired with
Margaret Qualley in the romantic thriller film
Stars at Noon, directed by French filmmaker
Claire Denis, and played the titular character's uncle in
Catherine Called Birdy, a medieval comedy film directed by
Lena Dunham, based on
the 1994 children's novel of the same name; both the films were met with generally positive reviews, with the former premiering at the
2022 Cannes Film Festival and winning the
Grand Prix. In late 2022, Eimear McBride wrote and directed
A Very Short Film About Longing. The film was screened at the
2023 BFI London Film Festival. It starred Alwyn, Natalia Kostrzewa and Lashay Anderson and was soundtracked by
Tindersticks. In 2024, Alwyn played a supporting role in
Kinds of Kindness, an
anthology film directed by Greek filmmaker
Yorgos Lanthimos. He also co-starred as Harry Lee Van Buren in Brady Corbet’s epic
The Brutalist, earning acclaim for his portrayal of the entitled son. In 2025, Alwyn made his professional stage debut as Heath in a modern adaptation of Henrik Ibsen’s ‘‘The Lady from the Sea’’ at the Bridge Theatre in London, appearing opposite Alicia Vikander and Andrew Lincoln. He received a nomination for Best Supporting Performer in a Play at the 2026 WhatsOnStage Awards for his performance. Later that year he appeared as Bartholomew in Chloé Zhao’s
Hamnet, a period drama based on Maggie O’Farrell’s novel. The film received widespread critical acclaim and earned eight nominations at the 98th Academy Awards, including for Best Picture, with co-star Jessie Buckley winning Best Actress. He also starred as Laertes in the modern adaptation of Shakespeare’s ‘‘Hamlet’’ opposite Riz Ahmed in the title role.
Music While in a relationship with American singer-songwriter
Taylor Swift, Alwyn contributed to the production of ten of her songs released from 2020 to 2022. Alwyn stated that "it came about from messing around on a piano, and singing badly," and then "being overheard by Swift, and being, like, 'Let's see what happens if we get to the end of it together'". He is credited as co-producer of the songs "
Exile", "
Betty", "
My Tears Ricochet", "
August", "
This Is Me Trying" and "
Illicit Affairs" on Swift's eighth studio album,
Folklore (2020); and was also co-writer of "Exile" and "Betty", under the
pseudonym William Bowery. "Exile" reached the top 10 of the charts in various countries, including number six on the US
Billboard Hot 100 and number eight on the
UK Singles Chart. At the
63rd Annual Grammy Awards in 2021,
Folklore won the
Album of the Year, earning Alwyn his first
Grammy Award for his producing credit on the record. Credited as Bowery, Alwyn also co-wrote "
Champagne Problems", "
Coney Island" and the title track on Swift's second 2020 album,
Evermore. In April 2022, Alwyn revealed to
The Wall Street Journal that the name "William Bowery" was derived from the first name of his great-grandfather William Alwyn, who was a music composer, and the last name in honour of the New York City neighbourhood
Bowery, where he had spent "a lot of time" when he first arrived in the U.S. On Swift's tenth studio album,
Midnights (2022), he is credited as co-writer of "
Sweet Nothing", again as Bowery. ==Personal life==