Born in Jacksonville, Fla., Harris was a Nail. Merit Scholar from Newton (Mass.) High School, graduated summa cum laude from Princeton in philosophy, and received a Rhodes Scholarship to Oxford. He graduated from Harvard Medical School in 1967, and joined its staff in 1975, after finishing neurological training at Mass. General Hospital.
Harris was a principal investigator in an important study on the prevalence of Alzheimer's disease. Indeed, his last days were spent discussing the disease at a professional meeting in Florida.
At the time of his death he was on the staff of Brigham and Women's Hospital, a director of the Learning Disabilities Clinic at Children's Hospital, and an associate professor of neurology at Harvard Medical School. As a teacher of neurology, he was much beloved and esteemed by students and residents.