Henrietta was one of three daughters of Sir Henry Hobart, 4th Baronet, a Norfolk landowner, by his wife Elizabeth. Her father died in a duel when Henrietta was aged eight, and her mother died four years later in 1701, leaving her an orphan at twelve. She then became the ward of Henry Howard, 5th Earl of Suffolk, marrying his youngest son, Charles Howard, later 9th Earl of Suffolk. The wedding was held at the church of St Benet, Paul's Wharf in London on 2 March 1706. They had one son, the future Henry Howard, 10th Earl of Suffolk. The marriage was unhappy; Charles was a wife-beater and compulsive gambler. In 1714, the couple travelled to Hanover, hoping to ingratiate themselves with the future George I of Great Britain. Henrietta met and became mistress to his son, the future George II, and was appointed a Lady of the Bedchamber to his wife, Caroline of Ansbach. In 1723, the now Prince of Wales made a financial settlement with her husband, who was also a member of his household, in exchange for her services as a royal mistress. Queen Caroline liked Henrietta, and was happy that the King kept a mistress she found congenial, although she would occasionally administer snubs to Henrietta in public. Henrietta was noted for wit and intelligence rather than for beauty. Henrietta and her husband officially separated around 1727, although there was no divorce; that would have required an act of parliament to be passed, with inevitable public scrutiny. Charles succeeded to the Earldom in 1731, allowing Henrietta to describe herself as Countess of Suffolk. Later, after Charles Howard's death in 1733, Henrietta remarried, in 1735, the Hon. George Berkeley, son of the Earl of Berkeley. After leaving the position of mistress to George II, Henrietta purchased land on the banks of the River Thames, having received a very large financial settlement from the King. Marble Hill House in Twickenham was built for her on this site by the architect Roger Morris, who collaborated in its design with Henry Herbert, 9th Earl of Pembroke, one of the "architect earls." When her second husband died, in 1746, she retired there permanently. She formed an intellectual circle, and her many friends included Charles Mordaunt, 3rd Earl of Peterborough, John Gay, and Alexander Pope. Her correspondents also included Horace Walpole and Jonathan Swift. Pope wrote of her, in his poem "On a certain lady at court": She is generally supposed to be the model for Chloe, a character type found in Pope’s Horatian Epistle To a Lady, and is a character in The Heart of Midlothian by Sir Walter Scott, who describes accurately her ambiguous friendship with Queen Caroline.