The Gunning sisters were much courted and admired, and in January 1752 Elizabeth was introduced to the Duke of Hamilton. This fateful meeting led to a whirlwind courtship and at a St Valentine’s Day party in Bedford House the Duke threw caution to the wind and demanded that a local parson marry them then and there. The parson refused as the Duke had not procured a licence and the banns had not been called. Undeterred by this setback, the Duke took his bride-to-be to the Mayfair Chapel, where they were married at midnight without a licence and with a ring taken from a bed curtain. Such ‘clandestine marriages’, although regarded as improper were legally binding and valid.
As Duchess of Hamilton, Elizabeth Gunning bore three children, but sadly the Duke passed away in 1758. She had not lost her allure, however, and attracted the attention of the Duke of Bridgewater, and entered into an engagement with this illustrious gentleman. However, for reasons that are not known, the engagement was terminated, and in 1759 she married John Campbell, Marquess of Lorne. In 1770 Elizabeth Gunning became the Duchess of Argyll when her husband succeeded to the dukedom, and she went on to have a further five children. Horace Walpole, who was clearly not a fan of the lovely Gunning sisters, said, "Who could have believed a Gunning would unite the two great houses of Campbell and Hamilton? For my part I expect to see Lady Coventry (Maria Gunning) Queen of Prussia. I would not venture to marry either of them these thirty years, for fear of being shuffled out of the world prematurely, to make room for the rest of their adventurers.”
Elizabeth was a great favourite with the royal family, and between 1761 and 1784 she served as a Lady of the Bedchamber to Queen Charlotte and King George III created her the Baroness Hamilton of Hameldon in her own right. The impoverished Irish beauty had become one of the greatest ladies in the land and she was also the darling of some of the period’s finest artists, being painted by both Gavin Hamilton and Sir Joshua Reynolds. She died aged 57 on 20th December 1790 at her London hime, Argyll House. She was buried at Kilmun in Argyllshire.