After completing his Architectural Engineering degree in 1995, John joined the Royal Engineers. He completed tours with Commandos and Gurkhas, deploying to Northern Ireland, Norway, Oman, Kosovo and Bosnia. He later commanded a bomb disposal squadron and a close support engineer regiment, including three tours of Helmand Province, Afghanistan. His staff tours included two years as a Military Assistant, a tour developing the UK’s offensive counter-IED strategy and time as the Army Pay Colonel. After attending Higher Command and Staff Course (HCSC), he took command of 8 Engineer Brigade, after which he was appointed Chief of Joint Force Operations, a tour which included deploying as the Joint Task Force Commander for the UK’s crisis response to Hurricanes Irma and Maria and supporting various other crisis response operations.

John left the Army in 2020 to join the Civil Service. He spent two years as Director Strategy and Enterprise Services in Defence Intelligence where he led transformation and corporate services. In March 2022, he moved to 10 Downing Street on a six-month loan, leading transformation and working as part of a broader Cabinet Office change programme. He returned to MOD in September 2022 as Director Defence Innovation where he led Defence's innovation portfolio, including being the UK representative on the NATO DIANA Board of Directors and leading the Innovation Working Group in AUKUS Pillar 2. After just over two years in this post, John left government for the first time to join the NATO Innovation Fund as their first Chief Adoption Officer.

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