Stewart has worked within the field of Intelligence and Security for the past 20 years, with experience across both the private and public sectors. Starting his career in 2004 in the Intelligence Corps of the British Army, Stewart entered the private sector in 2009 and has held several roles in Cyber Threat Intelligence (CTI) since then. These have included product development, service delivery and consulting, with his most recent roles involving the management of specialist teams involved in research into the cyber criminal underground and nation state threat actors.

Holding both a Master's in Computing and a Master of Letters in Terrorism Studies from St. Andrews University. Stewart was also among the first in the world to pass the CREST Certified Threat Intelligence Manager (CCTIM) examination.

Stewart’s research interests and work have always been at the intersection of technology, security, and people-focused issues. These unique areas of focus are laid bare within his role at arcX, where he is responsible for the design and delivery of the core CREST-related CTI courses and oversees the wider Cyber Threat Intelligence stream.