In 2006, he was selected to be part of Future Perfect, a writer's group attached to the Paines Plough theatre company. In 2007, he joined the company as their playwright-in-residence.[1]
His debut stage play, Salt Meets Wound, premiered at Theatre503 in May 2007.[2]
In April 2022, it was announced that he would adapt Studio Ghibli's 1988 animated film My Neighbour Totoro for the stage. Produced by the Royal Shakespeare Company and the film's original composer Joe Hisaishi, the play ran for a fifteen-week limited season at the Barbican Theatre in London from October 2022.[4] The play won five categories at the 2023 WhatsOnStage Awards, having been nominated in nine.[5] It also won six categories (out of nine nominations) at the 2023 Laurence Olivier Awards, including Best Entertainment or Comedy Play.[6][7] Morton-Smith dedicated his Olivier award to the memory of his stillborn daughter.[8]