His first notable role was as Sam, Liam Neeson's stepson, in Love Actually. He's known for providing the voice of Ferb in Phineas and Ferb, and for playing Jojen Reed in Game of Thrones. He also played the lead role of Jack Dawkins, aka The Artful Dodger, in The Artful Dodger.
He worked with director/writer Scott Frank on Netflix miniseries Godless and The Queen's Gambit, earning an Emmy Award nominationnote for his role in the latter.
Filmography:
- Hitler: The Rise of Evil (2003): Young Adolf Hitler
- Love Actually (2003): Sam, also reprised the role in Red Nose Day Actually (2017)
- Nanny McPhee (2007): Simon Brown
- Doctor Who (2007): Tim Latimer
- The Last Legion (2007): Romulus Augustus
- Phineas and Ferb (2007-2015): Ferb Fletcher (voice role)
- Bright Star (2009): Samuel Brawne
- Nowhere Boy (2009): Paul McCartney
- Game of Thrones (2013-2014): Jojen Reed
- The Maze Runner Series (2014-2018): Newt
- Thunderbirds Are Go (2015-present): John Tracy
- Wolf Hall (2015): Rafe
- Godless (2017): Whitey Winn
- The Queen's Gambit (2020): Benny Watts
- Dragon Rider (2020): Firedrake (voice role)
- The Artful Dodger (2023): Jack Dawkins/The Artful Dodger
