He was the fourth but second surviving son of Sir Edmund Wyndham (c. 1600–1681), and Christabella, daughter of Hugh Pyne of Cathanger, Fivehead, Somerset.
Christabella was the wet nurse for the future King Charles II and considered one of the most beautiful women of her day.
[3] The family went abroad after the end of the English Civil War, and Wyndham served as a Page of Honour to the exiled Charles II until 1660.
[7] Wyndham was a very popular MP in Southampton, where he earned a reputation as "a zealous assertor of the tenants’ rights" against their landlord.
[2] Through her uncle John Young, the Dean of Winchester, Wyndham inherited Cranbury Park, Hursley, where Sir Isaac Newton lived toward the end of his life.