(March 2009) Played Karl in "Over There" play by Mark Ravenhill (Royal Court Theater, London, England, UK).
(2012) He also appears in music video for Crystal Fighters' song "Champion Sound".
(2012) Treadaway appears in the music video for The Script's song "For the First Time".
(August 2012 - October 2012) Played Christopher in "The Curious Incident of the Dog in the Night-Time" play by Simon Stephens based on the novel by Mark Haddon (National Theatre, London, UK).
(2013) Appears in the music video for The Boxettes - "Puppet on a String".
(2017) Plays Nick in "Who's Afraid Of Virginia Woolf?" at the Harold Pinter Theatre. The cast includes Imelda Staunton (as Martha), Conleth Hill (as George) and Imogen Poots (as Honey).