On television, he is known for his role as Oscar Tully in the HBO series House of the Dragon (2024–).
[3] Around the age of 10, Barnes made his professional stage debut in the 2016 production of Bugsy Malone at the Lyric Theatre in Hammersmith.
[6] He was initially set to voice Pantalaimon in the BBC series His Dark Materials but withdrew; the role was taken over by Kit Connor.
[8] In 2023, Barnes made his television debut as Matthew Stonehouse in the 2023 ITV comedy-drama Stonehouse starring Matthew Macfadyen and Keeley Hawes[9] and appeared in Phaedra at the National Theatre,[10] which was nominated for a Laurence Olivier Award.
[11] The following year, Barnes joined the cast of the HBO fantasy series House of the Dragon, a Game of Thrones prequel, for its second season as Oscar Tully,[2] who becomes Lord of Riverrun and Lord Paramount of the Riverlands at a young age.