Dr R J Shephard is presently Professor Emeritus of Applied Physiology in the Faculty of Physical Education and Health and the Department of Public Health Sciences, Faculty of Medicine, University of Toronto. He was Director of the School of Physical and Health Education at the University of Toronto for 12 years (1979–91), and Director of the University of Toronto Graduate Programme in Exercise Sciences from 1964 to 1985.

He is also a Visiting Scientist at the Defence and Civil Institute of Environmental Medicine, a consultant to the Toronto Rehabilitation Centre, the Directorate of Active Living, Health and Welfare Canada, the University of New Brunswick (Fredericton), and the University of Quebec (Trois Riviéres). He has held academic appointments in the Department of Physiology and the Institute of Medical Sciences at the University of Toronto, the Centre des Sciences de la Santé, Université de Québec à Trois Riviéres, and the Hôpital Pitié Salpetriére, Université de Paris, and was Canadian Tire Acceptance Limited Resident Scholar in Health Studies at Brock University from 1994 to 1998.

Before moving to Toronto in 1964, he also held appointments in the Department of Cardiology (Guy's Hospital, University of London), the RAF Institute of Aviation Medicine, the Department of Preventive Medicine (University of Cincinnati), and the UK Chemical Defence Experimental Establishment (Porton Down, UK).

He holds four scientific and medical degrees from London University (BSc, MBBS, PhD, and MD) and honorary doctorates from Gent University (Belgium) and the Université de Montréal, together with the Honour Award of the Canadian Society of Exercise Physiology and a citation from the American College of Sports Medicine. He is a former president of the Canadian Association of Sports Sciences, a former president of the American College of Sports Medicine, editor-in-chief of the Year-Book of Sports Medicine and founding editor of the Exercise Immunology Review, a former editor in chief of the Canadian Journal of Sport Sciences, associate editor of the International Journal of Sports Medicine, and a member of the editorial board of many other journals.

He is the author of some 70 books on exercise physiology, biochemistry and immunology, and fitness in able bodied individuals and those with various types of disability, and he has published over 1400 scientific papers on related topics.