Professor Dempsey is a UCC graduate, he completed postgraduate training in Paediatrics in Ireland and later a Neonatal Fellowship at McGill University Health Centre, Montreal. He is the inaugural Horgan Chair in Neonatology at University College Cork, a Neonatologist at Cork University Maternity Hospital and is clinical lead at the INFANT Research Centre UCC.

He is a member of a number of international collaborations conducting randomised trials on different aspects of neonatal care (Premod 2, Safeboosc3 and  COSGOD trials). He leads a number of local clinical studies, supervising PhD students and junior doctors on many aspects of newborn medicine including cardiovascular support and the newborn microbiome.

He is a member of a number of international organisations including the European Society of Paediatric Research,  European Neonatal Echo Working group, European NIRS Working group and Pharmacology section of the European Society for Paediatric Research.

He has been awarded a number of Higher Degrees,  including a doctorate for work on Hypotension in the preterm infant,  an MSc in Health Care Ethics and Law and an MA in Teaching and Learning, focused on Simulation based procedural care. He has > 200 publications in newborn care.