His maternal grandfather, James Douglas Stewart, was professor of veterinary science at the University of Sydney and a member of the CSIRO.
[5] In 1961 he joined the just established School of Medicine at the University of New South Wales was the founder of the Department of Neurology.
[8] While in Massachusetts in 1963, he worked with the neurologist Raymond Adams on post-hypoxic myoclonus (now called the Lance-Adams syndrome).
[11][12] During his period at the Prince Henry Hospital, he conducted research on the physiology of migraine, with special reference to serotonin and its "effects on blood vessels and brain pathways involved in pain".
[13][14] This work led to the "groundbreaking" discovery of the triptan family of drugs, including (after collaborative research with the United Kingdom's Glaxo) of sumatriptan, the first clinically available triptan (on the market since 1991) and a key medicine now used to resolve acute migraine attacks.