He was born at Hothfield House in Kent. His mother was Mary, daughter of Lord John Philip Sackville, and on his father's death, on 10 April 1786, his maternal uncle, John Frederick Sackville, 3rd Duke of Dorset, acted as his guardian during his minority. He became hereditary High Sheriff of Westmorland from 1786 to 1825. In early life he spent much time abroad, especially in Vienna, where he formed an alliance with an Hungarian lady, Anne Charlotte de Bojanowitz, to whom he was married, under the Anglican rite, at St. George's, Hanover Square, on 28 February 1811. In politics Thanet's profile was low, but he generally supported the Duke of Bedford and the opposition to Pitt. In May 1798 he was present with Fox, Sheridan, Erskine, and other whig sympathisers at the trial of Arthur O'Connor at Maidstone. O'Connor was found not guilty, but was not discharged, since a warrant for his arrest for another offence was pending. Thanet and others were charged with having created a riot in the court and put out the lights in an attempt to rescue the prisoner, or at least to help his escape. The case was tried before Lord Kenyon at the king's bench on 25 April 1799. Sir John Scott prosecuted, and Erskine conducted the defence. Richard Brinsley Sheridan appeared to give evidence for the accused, and distinguished himself by parrying eight times, and finally evading, the question of Edward Law, counsel for the prosecution, ‘Do you believe Lord Thanet meant to favour the escape of O'Connor?’ Having been found guilty of riot and assault at Maidstone, Thanet was brought up for judgment on 3 May, and committed to the king's bench prison, the bail offered by the Duke of Bedford being refused. On 10 June he was sentenced to a year's imprisonment in the Tower of London and a fine of £1,000, and on his release he was ordered to give security for his good behaviour for seven years to the amount of £20,000. After his release the earl lived quietly at Hothfield, and became a popular agriculturist, regularly visiting the agricultural market at Ashford. He spent much time abroad, and he died at Chalons on 24 January 1825. He was buried on 7 Feb. at Rainham. Leaving no issue, he was succeeded in turn by his brothers Charles and Henry Tufton, eleventh and last earl of Thanet.
