Simon began directing at Cambridge University, where he received a degree in English. After graduating he founded Stray Dogs Theatre Company and began producing classical work including All’s Well That Ends Well, Anouilh’s Eurydice and the 18th-century opera Inkle and Yarico at the London Fringe.
In 2001 Simon became Associate Director at the Royal and Derngate Theatres in Northampton, where he worked as the deputy to the Artistic Director, Rupert Goold. His productions there included Everyman, Habeas Corpus and Relatively Speaking.
In 2005 Simon began a two year post graduate program at the London International School of Performing Arts (LISPA), where he studied physical theatre and devising. In 2008 he joined Tom Morris, as the Associate Director of The Bristol Old Vic, where he directed The Little Mermaid, Krapp’s Last Tape/A Kind Of Alaska, Faith Healer and Far Away.
In 2009 Simon became Associate Director of the Royal Court. While there Simon directed seven world premieres, including Routes, If You Don’t Let Us Dream, We Won’t Let You Sleep, NSFW, The Witness, Goodbye to All That, The Acid Test and Wanderlust.
Simon made his debut at the Royal National Theatre with Strange Interlude followed by Man and Superman. When Rufus Norris became the new Artistic Director of the NT in 2015, he invited Simon to become part of his team of permanent Associates. Since then Simon has directed The Beaux’ Stratagem, Twelfth Night and Antony & Cleopatra with Ralph Fiennes and Sophie Okonedo. Simon has also enjoyed working with the Royal Shakespeare Company. In 2014 he directed The Two Gentlemen of Verona followed in 2016 by an acclaimed Hamlet, which toured to the Kennedy Center, Washington D.C. In 2018, Simon returned to the RSC to direct Kathryn Hunter in the titular role in Timon of Athens. In 2019, Simon will made his Tokyo debut, directing a Japanese cast in Hamlet for Theatre Cocoon.
In 2019 he became the Artistic Director of the Shakespeare Theatre Company in Washington DC.
In 2020 he directed the first film to made inside the National Theatre Romeo and Juliet, bringing to life the backstage of this iconic arts venue.
In 2012 Simon was awarded the inaugural Evening Standard/Burberry Award for an Emerging Director.