After the Revolutionary War, Rush worked at the Pennsylvania Hospital. Rush was the treasurer of the United States Mint from 1797 to 1813. He became a fellow of the American Academy of Arts and Sciences in 1788. Rush returned to the University of Pennsylvania as a professor of medicine. William Henry Harrison was a student of Rush. Rush founded Dickinson College in 1773. Rush treated patients during the 1793 Philadelphia yellow fever epidemic. He was also one of the founders of the Pennsylvania Prison Society. Rush prepared Meriwether Lewis for the medical part of the Lewis and Clark Expedition.