Simon is a writer and actor. He co-wrote, and is an associate producer on the feature film, Better Man (2024 – dir: Michael Gracey). As part of his long-term collaboration with Michael Gracey, he was a creative consultant on Gracey's 2017 film, The Greatest Showman. 

Simon is an actor with thirty years experience, performing principal roles in the West End, Royal National Theatre and across major theatre companies in Australia. In 2015, He was awarded a Helpmann Award for his portrayal of Jean Valjean in Les Misérables.