[5] Through his paternal grandparents, Ann Dudley (1684–1776) and John Winthrop, F.R.S.

(1681–1747), he was a member of the Dudley–Winthrop family, a line that originates with Thomas Dudley—founder of Massachusetts and Winthrop's great-great-grandfather.

His paternal great-grandfathers were Joseph Dudley (1647–1720) and Wait Still Winthrop (1641/2–1717).

[6] He entered Yale in 1776 but left and graduated at Harvard in 1780.He was a lawyer and served as Treasurer for the Kennebek Proprietors in the late 18th century.

He was a member of the Ancient and Honorable Artillery Company of Massachusetts and also served as a state representative and senator.