Consultant Endocrinologist, Galway University Hospitals, Galway, Ireland. Professor of Diabetic Medicine, University of Galway. Seán Dinneen graduated from University College Cork Medical School in Ireland. After a period of postgraduate training in Ireland he travelled to the USA where he completed training in Internal Medicine and Endocrinology at the Mayo Clinic in Rochester, Minnesota. He was awarded a Mayo Foundation Scholarship and completed a Masters in Clinical Epidemiology at McMaster University, Hamilton, Ontario, Canada before returning to a staff position at the Mayo Clinic in the Division of Endocrinology with a joint appointment to the Division of Health Services Research. In 2000 he was appointed as a Community Diabetologist in Addenbrookes Hospital, Cambridge, UK, one of the first such appointments in the NHS. He returned to Ireland in 2005 as a Senior Lecturer in Medicine and Consultant Endocrinologist in Galway University Hospitals.

He was Head of the School of Medicine at the University of Galway from 2013 to 2016 and was appointed as a Personal Professor in Diabetic Medicine. He was Lead for the National Clinical Programme for Diabetes of the HSE from 2016 to 2022. In January 2025 he was appointed Clinical Lead for a National Diabetes Registry in Ireland.

His professional interests include developing and evaluating programmes of self-management education for people with diabetes, developing optimal models of community-based diabetes care and understanding the diabetic foot. He has secured research funding from the Health Research Board, Enterprise Ireland, Diabetes Ireland and the European Foundation for the Study of Diabetes.

In 2021 he was appointed National Lead for the PPI Ignite National Network tasked with building capacity for meaningful Public and patient involvement in health and social care research in Ireland. He has served on the Postgraduate Education Committee (2013 to 2020) and Guideline Oversight Committee (2023 to present) of EASD (European Association for the Study of Diabetes). He was an Editor with Diabetic Medicine (the journal of Diabetes UK) from 2015 to 2024. He is Clinical Lead for Schwartz Rounds in Galway University Hospitals.

Prof Dinneen is interested in incorporating teaching and learning in lived experience of diabetes into the undergraduate curriculum. From 2015 to 2020, along with colleagues in the Diabetes Centre in GUH, he helped deliver a Special Study Module (SSM) to 4MB students emphasising the challenges of living with a chronic disease. In 2025 he received funding from the Irish Network of Healthcare Educators (INHED) to incorporate learning from this lived experience SSM into the Foundation Year of the new UG curriculum in University of Galway.