Born on June 8, 1799 in Philadelphia, Pennsylvania, William Moore Meredith was the eldest son of William Tuckey Meredith (d. 1844), a successful attorney and after 1814 president of Schuylkill Bank, and who narrowly lost to Nicholas Biddle the presidency of the Bank of the United States.
William M. Meredith graduated from the University of Pennsylvania in 1812 (graduation at age 13 not being unusual at the time).