After securing a place to study English Literature at Trinity College Oxford, Oliver became actively involved in the university's dramatic society. Upon graduating he was awarded a scholarship to train at the London Academy of Music and Dramatic Art (LAMDA) and studied there for two years. Upon graduating from LAMDA, Oliver met Gregory Doran - the Artistic Director of the Royal Shakespeare Company (RSC) - and was offered the title role in Shakespeare's "lost play" Cardenio. Doran directed and Oliver performed the role to critical acclaim, cited as a "dashing professional debut" for Oliver by Mark Shenton writing for The Stage, noted for "a beguiling Cardenio" by Mark Taylor at the Independent and being telegraphed as a "talented young man on the path to future stardom" by Simon Tavener at London's leading theatre website WhatsOnStage. While at the RSC, Oliver also worked with acclaimed British playwright Antony Neilson. Other theatre roles followed, including The City Madam at the RSC and I Am A Camera, to name a few. Most recently Oliver reunited with Neilson for his original play Narrative in a part specifically written for Oliver by Neilson and performed at the Royal Court.