Benjamin Rush returned from medical study in Europe to Philadelphia in 1769 and became professor of chemistry at the College of Philadelphia. He combined private practice with teaching, publishing and political activity. His pamphlets addressed temperance, slavery and public affairs. He entered the Continental Congress in 1776 and signed the Declaration of Independence.

During the Revolutionary War he served in the army's medical administration and criticized the conditions endured by soldiers. Disputes over hospitals, supplies and leadership led to his resignation. He later supported the federal Constitution and participated in debates about education and the institutions needed by a republic. His reform interests included opposition to slavery, changes in criminal punishment and wider access to medical care, although his racial theories also reproduced serious prejudices.

Rush remained a Philadelphia physician and teacher. He helped found the Philadelphia Dispensary to treat people unable to afford private care and worked at Pennsylvania Hospital. During the yellow fever epidemic of 1793 he stayed in the city and treated many patients. His commitment to bloodletting and drastic purgatives provoked fierce controversy. These treatments reflected his medical theory but could harm patients, and his prominence should not be confused with the effectiveness of all his methods.

His Medical Inquiries and Observations upon the Diseases of the Mind appeared in 1812. He treated mental illness as a subject for physicians and advocated improvements in institutional care, while also employing restraints and procedures that later medicine rejected. Through publications, lectures, correspondence and apprenticeships, he influenced generations of American practitioners. His career joined revolutionary politics and social reform with medical authority, leaving a record of energetic public service as well as the dangers of confidently applying an inadequate theory of disease.