Dr McAlister is a professor in Western, where he is the director of its Office of Military Academic Medicine. His research interests include fundamental and clinical research, as well as the history of medicine. He is president of the James IV Association of Surgeons. Formerly, he was a general surgeon with expertise in transplantation and military medicine. He has been president of the Canadian Society of Transplantation and the Canadian Organ Replacement Registry. Dr McAlister served on the council of the Royal College of Physicians and Surgeons of Canada and was chair of its Region Advisory Committee for Ontario and Nunavut (RAC 3). He was co-editor-in-chief of the Canadian Journal of Surgery from 2013 until 2019. He was a regular force member of the Royal Canadian Medical Service, Canadian Armed Forces until 2019 and has deployed overseas many times. Awards received include The Queen Elizabeth Diamond Jubilee medal (2012), the Angus McLachlin chair of surgery (2014); the Canadian Medical Association John McCrae Memorial Medal (2019) and the Canadian Society of Transplantation lifetime achievement award (2019). Dr McAlister was made an officer in the Order of Canada in 2020.