[2] His breakthrough performance came when he played the role of Ian Curtis in the film Control, a biopic about the lead singer of the 1970s post-punk band Joy Division.

He played the role of Pinkie Brown in Brighton Rock alongside Helen Mirren, an adaption of Graham Greene's novel,[6] released 4 February 2011.

[2] He also starred in Walter Salles' film adaptation of Jack Kerouac's autobiographical On the Road playing the narrator and protagonist Sal Paradise.

[2] He also has a small role in the 2011 German comedy Woman in Love [de], in which his wife Alexandra Maria Lara plays the female lead.

In 2015, he played Benoit Labarie in Saul Dibb's film adaptation of Irène Némirovsky's novel Suite Française, opposite Michelle Williams, Matthias Schoenaerts, Kristin Scott Thomas and Ruth Wilson.

Riley played the 'not-so welcome' returning prodigal brother David in the 2018 film Happy New Year, Colin Burstead[8] by Ben Wheatley.