Dr. Leader is a respected and valued member of the Ajax and Pickering medical community. In 1981 he started practice in Ajax as a general internist. He was actively involved in the growth of the Ajax and Pickering General Hospital, where he served in many leadership roles, including chief of medicine, medical director of the intensive care unit, and director of the echocardiography laboratory.
Since 1992 his practice has focused on cardiology and cardiovascular medicine. In 1997 he joined the Cardiac Care Program at Rouge Valley Health System, and he continues on staff at Lakeridge Health Ajax and Pickering Hospital. In addition to his busy adult general cardiology practice, he has been active in clinical research and teaching.