In 1783, John Jacob left for Baltimore, Maryland, and was active first as a dealer in woodwind instruments, then in New York as a merchant in furs, pianos, and real estate. After moving to New York, John met and married Sarah Cox Todd (1762–1842). She worked alongside her husband as a consultant, and was accused of witchcraft after her success with the company in 1817. The accusations never led to legal action. They had eight children, including John Jacob Astor Jr. (1791–1869) and real estate businessman William Backhouse Astor Sr. (1792–1875).