Dr. Hamilton was born in Brandon, Vermont, and received his A.B. (1898) from the University of Vermont and his M.D. (1903) from the College of Physicians and Surgeons of Columbia University. Dr. Hamilton was an assistant physician at the Manhattan State Hospital, followed by seven years at the Utica State Hospital. In 1917, he served as Director of the Police Psychopathic Laboratory in New York City. He was Medical Director of the Philadelphia Hospital for Mental Diseases, followed by 13 years as Assistant Medical Director at Bloomingdale Hospital in White Plains (N.Y.).
He next served as Director of the Division on Hospital Service (1917–18, 1920, 1922-46) for the National Committee on Mental Hygiene. He directed the Mental Hospital Surveying Committee and served as a mental hospital advisor to the U.S. Public Health Service after 1936. He later served as superintendent of the Essex Hospital for the Insane in New Jersey. During WWI, Dr. Hamilton was on active duty with the U.S. Army from (1917–1919).
Dr. Hamilton was an instructor in psychiatry at the Women’s Medical College in Philadelphia (1920–22) and Associate Professor of Psychiatry at the University of Pennsylvania (1920–25).
Dr. Hamilton was a member of the American Medical Association, the American Psychopathological Association President (1938), and the American Association of Mental Deficiency. He contributed to the psychiatric literature and wrote the chapter on mental hospitals in the landmark book One Hundred Years of American Psychiatry, 1844–1944.
Dr. Hamilton served as President of the American Psychiatric Association (1946–47).