Dillane has played at the National Theatre in London and the Royal Shakespeare Company in Stratford-upon-Avon. At 24 he played Hamlet in Perth, Australia, directed by Ray Omodei. In 2000, he was Duke of Suffolk in the Olivier Award-winning Michael Boyd productions of Henry the Sixth parts 1, 2 and 3 in Stratford, London and Michigan.
Other television work includes playing Carter, the captain of the shape-changing justice robot Teselecta in Let's Kill Hitler and The Wedding of River Song in the 2011 series of Doctor Who, rogue spy John Richardson in Spooks, Australian conman Graham Poole in Hustle, Photographer and old flame Miles Brodie in Cold Feet, posh drug addict Theodore Platt in the first episode of Lewis and the relationship counsellor Ben in Men Behaving Badly as well as regular characters surgeon Sean Anderson in Casualty and Australian sergeant Brad Connor in the award-winning ITV series Soldier Soldier.
He was Wernher von Braun in the BBC television docudrama Space Race, Nero in Howard Brenton's play Paul at the National Theatre of GB and appeared several times as Stephen Maturin in the BBC radio adaptations of the Patrick O'Brian Aubrey–Maturin novels and Peter Guillam in three John le Carré adaptations.
In 2015, he played Charles Brandon, Duke of Suffolk in the BBC TV series Wolf Hall, and in 2016 he appeared in the lead role of DCI Michael Waite in the BBC TV series "Silent Witness".
