After earning a Bachelor of Science degree from the University of Guelph, Leslie graduated from the four-year naturopathic medical program at the Canadian College of Naturopathic Medicine (CCNM). She completed a two-year residency and is currently professor at CCNM providing instruction in pediatrics, philosophy and clinical medicine. She also supervises the clinical practice of fourth year interns.

Leslie is a member in good standing with the College of Naturopaths of Ontario - the regulation body of naturopathic medicine in Ontario. She also maintains membership with the Ontario Association of Naturopathic Doctors (OAND), the Canadian Association of Naturopathic Doctors (CAND).