Emmigrated with his parents to New England (1638), was the second graduate of Harvard College (1642), subsequently returned to England. Began career as a preacher; Member of House of Commons; Wounded at Battle of Dunbar; Founded National Exchequer Bank; Short spell in Tower; Had Samuel Pepys as his clerk; Secretary To The Treasury.

Cromwell appointed him scoutmaster-general of his army in Scotland, and resident ambassador at the Hague. There he is said to have arranged a secret meeting with ¤Charles II, warning him of Cromwell's intentions to seize him in Holland, and thereby saved the Royal Life. Charles retained him in office upon the Restoration (1660), and later created him a Baronet (1663).

He was given a grant of land in London's Whitehall district, in what is now called Downing Street.

Founder of Downing College. He was member of the Pariaments of 1710 and 1713, and kept his seat from 1722 until his death.