Nathaniel Chapman was born on 28 May 1780, in Fairfax County Virginia, the son of George and Amelia (Macrae) Chapman. He received his early education at the Alexandria Academy. At 17 he went to Philadelphia to study medicine, becoming a private pupil of Benjamin Rush (1745-1813), and eventually enrolling in the Medical School of the University of Pennsylvania, graduating in 1801. He then went to Edinburgh to further his medical studies, staying for three years, before returning to Philadelphia in 1804 to establish a practice.
While he actively practiced medicine for fifty years, Chapman is best known as a medical teacher, editor, and professional advocate. He became editor of the Philadelphia Journal of the Medical and Physical Sciences in 1820, a journal still published today (2000) as the American Journal of the Medical Sciences. From 1810 on he taught at the University of Pennsylvania, serving as professor of materia medica and professor of the theory and practice of medicine and clinical medicine. In 1817 Chapman founded the Medical Institute of Philadelphia, considered the first medical post-graduate school in the United States.
The principle publications of Chapman’s career are based on his lectures, such as his A Compendium of Lectures on the Theory and Practice of Medicine (1846).
As a professional advocate, Chapman served six terms as president of the Philadelphia Medical Society (a group similar to the College of Physicians of Philadelphia that amalgamated with the College in the 1830s). Also, he was elected by acclamation the first president of the American Medical Association in 1847. Chapman also served as President of the American Philosophical Society. Chapman was also a Fellow of the College of Physicians, elected in 1807.
A gifted teacher, charming, full of vitality, with a great sense of humor, Chapman was popular, and through his personality and competence rose to social prominence. He married Rebecca Biddle, daughter of Col. Clement Biddle, an officer in the Revolutionary War and close friend of George Washington. Chapman died in Philadelphia on 1 July 1853.