Jonathan was appointed as a Consultant Anaesthetist for Aneurin Bevan University Health Board in 2010. In 2014, he was also appointed as Assistant Medical Director for the Welsh Ambulance Service NHS Trust. He was involved in the planning of EMRTS from its early stages and was appointed as one of the founding consultants of the service when it went live in 2015.

Jonathan is passionate about the development of pre-hospital emergency medicine as a speciality. He has been directly involved in training for paramedics for over ten years, and junior doctors in pre-hospital medicine for the past four years. He has been an examiner for several years, for both the Diploma and Fellowship examinations in Immediate Care, for the Royal College of Surgeons of Edinburgh.​