Worsley was born in Reading, Berkshire to Peter and Enid (née Kay) Worsley. Her father taught geology at Reading University, while her mother is a consultant in educational policy and practice. Before going to university, Worsley attended Abbey School, Reading, St Bartholomew’s School, Newbury and West Bridgford School, Nottingham. She read Ancient and Modern History at New College, Oxford, graduating in 1995 with a BA First-class honours degree.

Worsley began her career as a historic house curator at Milton Manor, near Abingdon, in the summer of 1995. From 1996 to 2002, she was an Inspector of Historic Buildings for English Heritage in the East Midlands region. During that time she studied the life of William Cavendish, 1st Duke of Newcastle and wrote the English Heritage guide to his home, Bolsover Castle. In 2001, she was awarded a DPhil degree from the University of Sussex for a thesis on The Architectural Patronage of William Cavendish, first Duke of Newcastle, 1593–1676. The thesis was later developed into Worsley’s book Cavalier: A Tale of Chivalry, Passion and Great Houses.

In 2005, she was elected a senior research fellow at the Institute of Historical Research, University of London; she was also appointed visiting professor at Kingston University.

In 2011, Worsley presented the four-part television series If Walls Could Talk, exploring the history of British homes, from peasants’ cottages to palaces; and the three-part series Elegance and Decadence: The Age of the Regency. In 2012 she co-presented the three-part television series Antiques Uncovered, with antiques and collectibles expert Mark Hill, and (broadcast at the same time) Harlots, Housewives and Heroines, a three-part series on the lives of women after the Civil War and the Restoration of Charles II. Later that year she presented a documentary on Dorothy Hartley’s Food in England as part of the BBC Four “Food and Drink” strand.

Worsley lives in Southwark by the River Thames in south London with her husband, architect Mark Hines, whom she married in November 2011. With reference to having children, Worsley says she has been “educated out of normal reproductive function”. She later said her statement had been “misinterpreted and sounded darker than I’d intended.”

During 2002–2003, she was Major Projects and Research Manager for Glasgow Museums before becoming Chief Curator at Historic Royal Palaces, the independent charity responsible for maintaining the Tower of London, Hampton Court Palace, Kensington Palace State Apartments, the Banqueting House in Whitehall and Kew Palace in Kew Gardens. She oversaw the £12 million refurbishment of the Kensington Palace state apartments and gardens completed in 2012.

In 2014, the three-part series The First Georgians: The German Kings Who Made Britain explored the contributions of the German-born kings George I and George II. The series explained why the Hanoverian George I came to be chosen as a British monarch, how he was succeeded by his very different son George II and why, without either, the current United Kingdom would likely be a very different place. The series emphasises the positive influence of these kings whilst showing the flaws in each. A Very British Romance, a three-part series for BBC Four, was based on the romantic novels to uncover the forces shaping our very British idea of ‘happily ever after’ and how our feelings have been affected by social, political and cultural ideas.

Worsley has published a number of books, many guides to houses and the like. Courtiers: The Secret History of the Georgian Court (2011) is her most recent work on history. In 2014, BBC Books published her book, A Very British Murder, which was based on the series. In April 2016, Worsley published her debut children’s novel, Eliza Rose, about a young noble girl in a Tudor Court. In 2017, Worsley published a biography of Jane Austen titled Jane Austen at Home: A Biography. Lucy Worsley also wrote Lady Mary, a historical teen book that details the life of Lady Mary.

In 2016, Worsley presented the three-part documentary Empire of the Tsars: Romanov Russia with Lucy Worsley in January and Lucy Worsley: Mozart’s London Odyssey in June. In September 2016, she was filming an upcoming series A Very British History for BBC Four. In December she presented and appeared in dramatized accounts of the three-part BBC series Six Wives with Lucy Worsley. In 2017, she presented a three-part series entitled British History’s Biggest Fibs with Lucy Worsley, debunking historical views of the Wars of the Roses, the Glorious Revolution and the British occupation of India.

In 2019, Worsley presented American History’s Biggest Fibs, looking at the nation’s founding story and American Revolution, the American Civil War, and the Cold War.

In May 2019, Worsley’s speech about Queen Victoria, subsequent to her 2018 book Queen Victoria: Daughter, Wife, Mother, Widow (St. Martin’s Press, 1 August 2018), included comments indicating that Albert, Prince Consort did not deserve all of the accolades he had received.