Stuart graduated from the University of Oxford and trained at the Royal Military Academy Sandhurst, commissioning as an Infantry Officer. Over a 30‑year career in the military and intelligence sectors, he held senior leadership roles and commanded forces on operations worldwide, including the Gulf War and Afghanistan.

He later specialised in planning and leading high‑risk covert missions. Since retiring from public service, Stuart is a Director of a logistics company and the Founder of Dark Blue Consultancy, providing leadership training to senior managers within the intelligence and security sectors.