On 2 April 1717, he married Lady Harriet Godolphin, daughter of the 2nd Earl of Godolphin and granddaughter of John Churchill, 1st Duke of Marlborough.
The Duchess suffered from poor health and the couple had no children.

In 1731, at Houghton Hall, Sir Robert Walpole's country house in Norfolk, the Duke, with the Duke of Lorraine (later the Holy Roman Emperor), was made a Master Mason by the Grand Master, Lord Lovell, at an Occasional Lodge.
In 1739, at the creation of London's Foundling Hospital, he acted as one of the charity's founding governors.
On 2 April 1717, he married Lady Harriet Godolphin, daughter of the 2nd Earl of Godolphin and granddaughter of John Churchill, 1st Duke of Marlborough. The Duchess suffered from poor health and the couple had no children.
In 1731, at Houghton Hall, Sir Robert Walpole's country house in Norfolk, the Duke, with the Duke of Lorraine (later the Holy Roman Emperor), was made a Master Mason by the Grand Master, Lord Lovell, at an Occasional Lodge. In 1739, at the creation of London's Foundling Hospital, he acted as one of the charity's founding governors.
Thomas Pelham-Holles, 1st Duke of Newcastle