Born in 1732 in a house that is on the grounds of Historic Rittenhouse Town (site of British North America's first paper mill), Rittenhouse showed talents in mathematics and mechanical arts from an early age. On his father's farm, he constructed case clocks, some of which included small orreries, and also telescopes and surveying instruments. He was a leader in the collective effort to view the transit of Venus in 1769. In 1774 Rittenhouse became the city surveyor of Philadelphia, and he constructed an observatory in the city.
Rittenhouse was a professor of astronomy at the College of Philadelphia from 1779 to 1782. During the Revolution, he was on the Philadelphia Committee of Safety, supervised the manufacture of ammunition, and was a member of the 1776 Pennsylvania Constitutional Convention. He served as a Trustee of the University during its years of dissolution and reorganization as the University of Pennsylania, beginning in 1779 until his death in 1796. He also served as Treasurer of Pennsylvania and as director of the United States Mint.