[9][10] He starred in the 2017 four-part series Howards End as Leonard Bast, a young bank clerk, opposite Hayley Atwell.

[11] That same year, he starred in the short film KIN, and appeared in a season 7 episode of the HBO series Game of Thrones as Koner, a Stark soldier.

[5] In 2018, Quinn played Enjolras in the BBC One adaptation of Les Misérables and made his feature film debut in Overlord.

The following year, he starred alongside Molly Windsor in the thriller film Make Up and portrayed Tsarevich Pavel in the Sky Atlantic miniseries Catherine the Great.

He starred with Lupita Nyong'o in the horror film A Quiet Place: Day One, directed by Michael Sarnoski, which was released in June 2024.

[24][25] In February 2024, it was announced that Quinn was cast as Johnny Storm / Human Torch in the Marvel Cinematic Universe film The Fantastic Four: First Steps (2025).