Stephen O’Rahilly graduated in Medicine from University College Dublin in 1981. From 1982 to 1991 he undertook postgraduate clinical and research training in general medicine, diabetes and endocrinology in London, Oxford and Harvard. In 1991 he obtained a Wellcome Trust Senior Clinical Fellowship and established his laboratory at the University of Cambridge. In 1996 he was appointed to a newly created Chair of Metabolic Medicine and in 2002 to the Chair of Clinical Biochemistry and Medicine at the University of Cambridge. He is the Co-Director of the Wellcome Trust-MRC Institute of Metabolic Science and Director of the MRC Metabolic Diseases Unit. His research has been concerned with the elucidation of the basic causes of obesity and Type 2 diabetes at a molecular level and the translation of those discoveries into improved diagnosis and therapy for patients. His work has uncovered several previously unrecognised genetic causes of these diseases including some that are amenable to specific treatment. He has won many awards for his work including the Society for Endocrinology Medal, the European Journal of Endocrinology Prize, the Novartis International Award for Clinical Research in Diabetes, the Clinical Investigator Award of the Endocrine Society, the Heinrich Wieland Prize, the Rolf Luft Award, the Feldberg Award, the Society for Endocrinology Dale Medal, the InBev Baillet-Latour Prize for Health, the Ulysses Medal, the Zulch Prize and the Baly Medal. He was elected to the Academy of Medical Sciences in 1999, to the Royal Society in 2003, to the US National Academy of Sciences in 2011 and is an Honorary Member of the German Society for Internal Medicine. He has received honorary doctorates from the Universities of Dundee, Warwick and Buckingham and from University College Dublin. In 2013 he was appointed a Knight Bachelor for services to medical research. He has a continuing commitment to clinical practice and the teaching of medical students. He has made important contributions to the development of infrastructure for clinical research on the Addenbrooke’s campus. He has been a successful mentor of young scientists and clinician-scientists. He has contributed more generally to UK science through his Chairmanship of the Wellcome Trust Clinical Interest Group, the Medical Research Society and of the MRC Translational Research Overview Group; through his previous membership of the MRC Strategy Board and his service on the research advisory committees of several charities and companies.