Having graduated from high school at the age of 15, Harrison attended the University of Michigan, where he also completed one year of medical school before transferring to Johns Hopkins School of Medicine in the fall of 1919. He completed his internship at Peter Bent Brigham Hospital in Boston, returned to Hopkins for further training in internal medicine, and completed his residency at Vanderbilt University where he served as the first Chief Resident in the Department of Medicine.
Harrison specialized in cardiology and the pathophysiology of heart disease. Harrison"s special field of interest was cardiovascular medicine as well as the pathophysiological mechanisms of disease. His name is best known among medical practitioners as the founding editor and editor-in-chief of the first five editions of Harrison"s Principles of Internal Medicine.
The text initiated several unique approaches to medical textbook writing, and remains, in its current edition, one of the most widely read and regarded textbooks in medicine.
Harrison"s career included extensive work in research, publishing, medical education, and medical practice. He taught at Vanderbilt University"s school of medicine, at what was then the Bowman Gray School of Medicine at Wake Forest University in North Carolina and at what is today the University of Texas Southwestern Medical School in Dallas, Texas.
Harrison spent the greatest part of his teaching career at the University of Alabama School of Medicine (UASOM) in Birmingham, Alabama, where he served as Dean and chairman of the Department of Medicine. At UASOM, Harrison helped initiate a rapid period of growth that included recruitment of nationally known physicians from the faculties of such institutions as Harvard University and the Mayo Clinic.
This period saw UASOM rise from local to international prominence.
The Tinsley Harrison Research Tower at UASOM is named in his honor, among other sites of interest. Harrison died in Birmingham at the age of 78. The Montgomery Advertiser called the book "a superb examination of an extraordinary doctor"s life, seen through the lens of a turbulent century of medical and social change" and the Anniston Star calls it a "finely crafted biography." Additionally, the current Internal Medicine Residency at UAB is named after Harrison.