Henry trained at LAMDA. He is an Olivier award-winning writer and has been a member of Mischief Theatre since 2009.

Theatre includes: The Play That Goes Wrong (writer/actor, winner 2015 Olivier Award and WhatsOnStage Award for Best New Comedy). Peter Pan Goes Wrong (writer/actor, 2016 Olivier Award nominee for Best New Comedy), The Nativity Goes Wrong (writer), The Comedy About a Bank Robbery (writer/actor) and The Busy Body (Southwark Playhouse).

Television includes: Peter Pan Goes Wrong (BBC1) and A Christmas Carol Goes Wrong (BBC1).