Dr. Hallett obtained his A.B. and M.D. at Harvard University, had his internship in Medicine at the Peter Bent Brigham Hospital and his Neurology training at Massachusetts General Hospital. He had fellowships in neurophysiology at the NIH and in the Department of Neurology, Institute of Psychiatry in London, where he worked with C. David Marsden. Before coming to NIH in 1984, Dr. Hallett was the Chief of the Clinical Neurophysiology Laboratory at the Brigham and Women's Hospital in Boston and worked his way up to Associate Professor of Neurology at Harvard Medical School.
He is currently Chief of the Medical Neurology Branch and Chief of its Human Motor Control Section. He is now President of the International Federation of Clinical Neurophysiology. He has been President of the Movement Disorder Society and Vice-President of the American Academy of Neurology. Among many awards, in 2012 he became an Honorary Member of the American Neurological Association , and in 2014 won the Lifetime Achievement Award of the American Association of Neuromuscular and Electrodiagnostic Medicine.His research activities focus on the physiology of human voluntary movement and its pathophysiology in disordered voluntary movement and involuntary movement.