He is best known for playing Marius in Les Misérables in both its 30th Anniversary international production as well as at the Queen's Theatre and Fabrizio in The Light in the Piazza at the Royal Festival Hall.
[8] Houchen played Lieutenant Joseph Cable in the 2022 Chichester Festival Theatre production of South Pacific, at the Manchester Opera House, Sadler's Wells and UK tour.
[9] The cast also included Julian Ovenden as Emile de Becque, Gina Beck as Ensign Nellie Forbush and Joanna Ampil as Bloody Mary.
The show played at the Criterion Theatre with a cast including Lauren Drew as Celine Dion, Darren Bennett as Victor Garber/Luigi, Jordan Luke Gage as Cal, Stephen Guarino as Ruth and Kat Ronney as Rose.
In October 2024 he supported a charity concert of the musical I Am Harvey Milk at Cadogan Hall, based on the life of the queer politician, with profits going to Stonewall.