The son of Henry Ponsonby and Dorothy Sands of Cumberland; he was a cavalry officer under Cromwell, Sheriff of County Wicklow (1654), and founder of the Ponsonby dynasty.

REFERENCES TO Sir John Ponsonby:

Thomas Creevey to Elizabeth Ord, 15 September 1828 in The Creevey Papers: A Selection from the Correspondence & Diaries of the late Thomas Creevey, M.P. (London: John Murray, 1903)