Born in 1792 as John Lambton, he came from a wealthycoal-owning family in County Durham.
After Eton, he served for two years in the 10th Hussars, thenas MP for Durham from 1813 to 1828.
A keen cricketer and lover of horse-racing in his youth, he became known as Radical Jack for his support of universal suffrage and workers' rights, and for his anti-establishment speeches in Parliament, in 1819 denouncing the use of troops against a reform meeting in Manchester (the Peterloo Massacre).
Enobled in 1827, as Lord Privy Seal in the Whig administration of his father-in-law, Earl Grey, in 1830, he was commissioned to draft a Reform Bill, which eventually passed in 1832.
He was appointed Ambassador to Russia 1835-7,and in 1838 Governor-General of Canada, where his recommendations for local democracy and the union of Upper and Lower Canada were controversial. He resigned after five months.
He supported Humphry Davy's experiments on the miners' safety lamp, and Lambton Castle was one of the first houses in England to be lit by gas.
Despite vast wealth he was in many ways an unlucky man: his first wife died young, as did four of his children. He suffered from poor health and insomnia, and often seemed arrogant, surly and short-tempered, at least to his social equals. Palmerston described him as ‘sullen, silent,& sulky … not condescending to take part in the discussions of mortal men’. He was, however, a popular hero, and found time in his busy life to own and sail Jack o' Lantern (schooner, 140 tons, 1826-8) and the cutter Louisa (162 tons,1833-7). He was renowned for his hospitality in Cowes, where he died in 1842, aged forty-eight. His remark to Thomas Creevey that 'a man might jog on' with an income of £40,000 a year earned him the nickname KingJog, or Jog Along Jack.