Born in Ashbourne, Derbyshire, on 15 August 1876, Jourdain's father was Francis Jourdain (1834–1898), a vicar and her mother, Emily, was the daughter of the surgeon and pioneer of ovariotomy, Charles Clay. One of ten children, her siblings included the writer and academic Eleanor Jourdain, the ornithologist Francis Charles Robert Jourdain and the mathematician Philip Jourdain.^[1]

Jourdain attended the University of Oxford where she studied classics obtaining a third-class degree.^[1] While there she met actress Janette Ranken and the pair moved to London, where they lived together.^[2] The relationship came to an end when Ranken married Ernest Thesiger in 1917.^[2]

The finely honed writing that distinguishes Jourdain's work must be partly credited to careful pre-editing by her lifelong friend and domestic partner, the novelist Ivy Compton-Burnett. The couple lived together from 1918 until Jourdain's death in 1951. Members of their circle speculated on whether they were lovers: Compton-Burnett referred to herself and Jourdain as "neutrals".^[3] Jourdain's papers are archived at the Victoria and Albert Museum, London, but some of her unpublished translations of poems by Jose Maria de Heredia, Pontus de Tyard and Gérard de Nerval are among Compton-Burnett's papers at King's College, Cambridge.^[4]

Jourdain's Regency Furniture (1931) covered new ground in extending the "classic" period of English furniture design forward to 1830. With Ralph Edwards, Keeper of Furniture and Woodwork at the Victoria and Albert Museum, she co-wrote Georgian Cabinet-Makers (1944, 1951), a series of biographies of the major furniture-makers of England from the Restoration of Charles II to 1800. Their studies were based on archival work, which had not been a strong feature of previous connoisseurship. As revised by Edwards, their biographies remained standard works until they were superseded by the work of Peter Ward-Jackson, Christopher Gilbert, Helena Hayward, and members of the Furniture History Society.

Most of Margaret Jourdain's works went through several printings.

• English Interior Decoration and Furniture of the Later XVIIIth century 1760-1820: An Account of Its Development and Characteristic Forms 1922; 1924. (B.T. Batsford)
• English Decorative Plasterwork of the Renaissance 1926; 1933 (B.T. Batsford)
• Regency Furniture, 1795–1820 1931 (1934?); revised and extended to 1830 by Ralph Fastnedge
• Georgian Cabinet-Makers 1944; 1946; revised 1951 (3rd edition 1955) (with Ralph Edwards)
• The Work of William Kent. Artist, Painter, Designer and Landscape Gardener (Country Life Books 1948): the first modern reassessment of William Kent, with an introduction by Christopher Hussey
• Jourdain, Margaret; Jenyns, Soame (1967), Chinese Export Art in the Eighteenth Century (2 ed.), Spring Books (First edition appeared in 1950)
• English Interior Decoration, 1500 to 1830: A Study in the Development of Design (B.T. Batsford 1950)
• English Furniture (Country Life Books 1950)

• Hilary Spurling: Ivy: The Life of Ivy Compton-Burnett (includes many personal details of Margaret Jourdain)