Career
Tankerville was the son of Charles Bennet, 2nd Earl of Tankerville. Tankerville was returned to Parliament for Northumberland in 1748, a seat he held until the following year, when he was unseated on petition. In 1753 he succeeded his father in the earldom and took his seat in the House of Lords.
Lord Tankerville married Alice, daughter of Sir John Astley, 2nd Baronet, in 1742.
She died in 1755. Tankerville survived her by twelve years and died in October 1767, aged 51.