Career
At the 1831 general election his father bought him a seat as Member of Parliament (MP) for the rotten borough of Weobley, alongside his brother Lord Henry Frederick Thynne. The borough was disenfranchised under the Reform Act 1832, which he and his brother had repeatedly voted against.
Despite having been given £20,000 by his father when he married in 1830 (equivalent to £2,197,000 in 2025), by 1832 Thynne's marriage and finances were in deep trouble. His wife was estranged from him, and he was repeatedly sued by his creditor Thomas Slingsby Duncombe; in response he canvassed against Dubscombe at the Finsbury by-election in 1834, and at the following year's general election.
In 1837, he fought a duel on Battersea Fields with a Mr. Passmore, over "a young lady". Each fired three shots without effect.
In 1835 his father gave him a further £60,000 to clear his debts (equivalent to £6,591,000 in 2025). However, after his father's death in 1837, his family cut him off, and by August of that year he was imprisoned for debt in the Queen's Bench Prison in Southwark.
Thynne and Dunscombe resolved their quarrel in November, triggering Thynne's release from prison and allowing him to avoid bankruptcy.
When Thynne was discharged from insolvency at the end of that month, the court was told that his debts were £221,059 (equivalent to £24.8 million in 2025), which The Spectator described as an "enormous sum".
After the death of Elizabeth's father, when his estate was reported at nearly £3 million
(equivalent to £337 million in 2025), she unsuccessfully sued her family for more of her father's wealth (having been given £100,000 on her marriage, equivalent to £10,985,000 in 2025). Her estate was worth only £3,000 when she died in 1849.
Thynne married again in 1853, to Cecilia Gore, daughter of the novelist Catherine Gore. As a girl, Cecilia had been famous for her wasp waist.
The historian Macaulay described the union in his memoirs as "the noosing of a young – or rather a defiant young flirt to an old roué".
Thynne was a skilled marksman who in 1851 shot a golden eagle with a rifle at a hundred yards range, while deer stalking in Scotland as a guest of the Earl of Malmesbury. The killing of the 8.5 pounds (3.9 kg) bird was reported to be the only instance of a flying eagle being killed with a single ball.
He resumed his military career in 1855, when he was appointed as a cornet in the Wiltshire Yeomanry Cavalry. In 1863, he was commissioned as a lieutenant in the 18th Somerset Volunteer Rifle Corps