Prof Smith is a clinician-scientist specialising in aerospace medicine, cardiopulmonary physiology and anaesthetics. He is a Consultant Anaesthetist at the Queen Elizabeth Hospital in Adelaide, and is Clinical Professor at Adelaide University and Visiting Professor of Aerospace Medicine at King's College London. He previously led aerospace medicine research at King’s College London, an international centre of excellence in the field, before relocating to Australia in 2024. Prof Smith is a former Rhodes Scholar and Churchill Fellow and moved to King's from Oxford in 2017. He has led many national and international research collaborations, and has undertaken studies in challenging and extreme environments including high-G human centrifuges, parabolic ‘zero-G’ flights, commercial airline flights and at high altitude in the remote Andes of Peru, as well as many hypoxia/altitude chambers and facilities (normobaric and hypobaric).

His research has been awarded international prizes including the Ernsting, Liljencrantz and Tuttle Awards from the Aerospace Medical Association (AsMA), and he is an elected Fellow of AsMA and Academician of the International Academy of Aviation and Space Medicine. In 2019 he gave the Australasian Society of Aerospace Medicine's John Lane Oration in Sydney. Prof Smith led the King's MSc in Space Physiology and Health in collaboration with ESA’s European Astronaut Centre in Germany for several years, and he continues to teach on KCL's Diploma in Aerospace Medicine as Visiting Professor.

Clinically, Prof Smith has extensive experience in anaesthesia for major high-risk surgery, as well as broad experience as a flight doctor in aeromedical critical care across multiple aircraft types and 20+ countries. During the COVID pandemic he was part of the critical care Mobile Emergency Rapid Intubation Team responsible for all intubations across Guy’s and St Thomas’ Hospitals in London. Prof Smith has led many collaborations extending across academia, commercial industry, the military, the aviation/space regulator and space agencies including NASA, ESA and the UK Space Agency.

He has served in senior professional and government advisory roles including the UK Space Agency's principal advisory body for exploration (Space Exploration Advisory Committee) and the UK Medical Research Council (as Advisor in Aerospace Medicine). He is a past Chair of the Royal Aeronautical Society's Aerospace Medicine Group and a former Macintosh Professor of the Royal College of Anaesthetists, London.