David Leonard graduated from the University of Sydney in medicine in 1964 and, after working in general medicine and general practice in Sydney, Adelaide and New Guinea, entered post graduate training in psychiatry in London and Edinburgh,. He returned to Melbourne, Australia in 1971. He worked in public sector services, particularly focussing on people with psychotic disorders and personality disorders. He became director of a number of psychiatric services over the next 25 years. He was actively involved in undergraduate and postgraduate teaching and patient advocacy, through work with community organisations.
Over the last 12 years he has worked in full time private practice at the Albert Rd Clinic where he is associated with the Professorial Unit of the University of Melbourne. His work there has focussed on trauma based disorders with a particular interest in dissociative disorders
In 2010 he was made a Member of the Order of Australia for services to psychiatry