Dr. McCullough got his MBbch BAO (bachelor of medicine, bachelor of surgery and obstetrics) from the Royal College of Surgeons in Ireland in 1996. Following his internship, he was awarded a Teaching Scholarship from RCSI during which time, he completed his Masters in Anatomy. After basic surgical training he was awarded a Post-Graduate Research Scholarship from Trinity College Dublin in Ireland, in investigating post-operative gastric function. Dr. McCullough gained a Certificate of completion of higher surgical training at North Thames foundation school. After he had achieved his Certificate of Completion of Specialist Training in 2009, he was awarded an Ethicon Laparoscopic and Pelvic Floor Fellowship at University College Hospital where he was appointed as Clinical Lead of Surgical Gastrointestinal Unit and Surgical Lead of the Intestinal Failure Unit at University College Hospital, London, UK.