Lillie married Irish landowner Edward Langtry in 1874. Some say that the attraction to Edward was because of his yacht and that he insisted he take her away from Jersey and set up home in London. Lillie did not begin her stage career until several years later after her husband had become bankrupt. She also had a daughter who was born in 1881, Jeanne Marie Langtry (who married Sir Ian Malcolm of Poltalloch in 1902, had four children, and died in 1964), and whose father was definitely not Lillie's husband. The child's actual father was reportedly Lillie Langtry's lover Prince Louis of Battenberg (later 1st Marquess of Milford Haven, 1854-1921), who married Queen Victoria's granddaughter Princess Victoria of Hesse and the Rhine in 1884 and became father of Earl Mountbatten of Burma, the last Viceroy of India, and grandfather of Prince Philip, Duke of Edinburgh. A recent biography of Langtry suggests that another of her lovers, Arthur Jones, may have been Jeanne Marie's father, though Prince Louis's son, Lord Mountbatten, always maintained that his father was the one.
Lillie's heyday as a society beauty culminated in her becoming a semi-official mistress to the Prince of Wales, Queen Victoria's son Albert Edward ("Bertie"), the future king Edward VII. Other lovers included wealthy Britons Robert Peel and George Baird. Among her friends were the Irish writer Oscar Wilde and the American artist James McNeill Whistler. She was for a time the manager of the Imperial Theatre and also manufactured claret at her 4,200 acre (17 km²) winery in Lake County (northern) California, which she purchased in 1888 and sold in 1906.
In 1887 Lillie became an American citizen, and divorced her husband the same year in California. In 1899, she married the much younger Hugo Gerald de Bathe, who would inherit a baronetcy, and became a leading owner in the horse-racing world, before retiring to Monte Carlo. She died there in 1929, and was buried in the graveyard of St. Saviour's Church in Jersey - the church of which her father had been rector.