Dr O’Connor graduated from the Royal College of Surgeons Medical School (RCSI) in 2002. He completed Higher Specialist Training in Ireland and then completed four years of clinical and research fellowship training in interventional cardiology in Paris, France in two of the largest centres for cardiovascular care in Europe, Pitié Salpêtière University Hospital and Institut Cardiovasculaire Paris Sud (ICPS), Massy, Paris. At both centres, he performed a high volume of procedures in percutaneous coronary intervention and stenting, peripheral and transcatheter valvular interventions. He was conferred MD by thesis by the National University of Ireland (NUI) in 2013 for clinical research undertaken with the ACTION Study Group at Institut de Cardiologie, Pitié Salpêtière University Hospital (Paris 6 – Sorbonne). He is working in St James’s Hospital since 2016 as an interventional cardiologist. He is an honorary lecturer for the Trinity School of Medicine.