[1] Thornley played Dodge in the original cast of the musical London Road at the Royal National Theatre, a role which he later reprised in the film version in 2015.

[2] In 2016 he played Ron Weasley in the original London cast of Harry Potter and the Cursed Child at the Palace Theatre in the West End.

[4] Thornley reprised his role as Weasley on Broadway at the Lyric Theatre in 2018[5] and again in 2020.

[3] For video games, Thornley provided the voice for Olgierd von Everec in the Hearts of Stone expansion for The Witcher 3: Wild Hunt in 2015.

In 2018 he voiced a major protagonist named Addam Origo in Xenoblade Chronicles 2: Torna – The Golden Country.