Lavery, Lady Hazel (1880–1935), artist, model, actress and socialite, was born 14 March 1880 at 514 North Avenue, Chicago, Illinois, the daughter of Edward Jenner Martyn (1846–1897), a self-made man who became vice president of Armour & Co. (a successful meat packing firm) and vice-president and director of the Union Stock Yard and Transit Company of Chicago, and Alice Louise (née Taggart) (c. 1857–1909), daughter of John (‘J. P.’) Taggart (1819–1908) a hardware merchant of Fond du Lac, Ripon, Wisconsin. Hazel had one sibling: Dorothea Hope (‘Dorothy’) Martyn (1887–1911), playwright, whose sole surviving work (all others she destroyed herself) was a farce in one act entitled Grove Eden published by R. R. Donnelley & Sons, 1912. Dorothy suffered from anorexia nervosa and died 13 October 1911 in Chicago aged twenty-three. Her death alienated Hazel from the land of her birth and afterwards she disassociated herself from America.
Hazel was educated at Sleboth–Kennedy School, Chicago, Kemper Hall, Kenosha, Wisconsin, and Miss Masters, Dobbs Ferry, New York. She studied etching in Paris in 1902. Sketches by Hazel Martyn was published by A. C. McClurg & Co. in Chicago. That year she returned to Paris and studied dry-point etching under Edgar Chahine. In December 1903 she married Dr Edward (‘Ned’) Livingston Trudeau junior, son of the founder of the tuberculosis sanatorium in the Adirondack Mountains in upstate New York. She was widowed in May 1904 following Ned Trudeau's untimely death from an embolism. Her daughter Alice Trudeau (1904–1991) was born on 10 October 1904 in Chicago. (Alice spent most of her life in Ireland and her second marriage was to the historian Denis Gwynn (qv)). In 1908 an illustration of her painting Sylvia was the frontispiece in Joseph Medill Patterson's A little brother of the rich first published by Grosset & Dunlop, New York.
In 1909 Hazel Martyn Trudeau married Belfast-born artist John Lavery (qv) – it was also his second marriage. They had met in 1903 in the artists’ colony of Beg-Meil in Brittany, when she was engaged to Trudeau. Living at 5 Cromwell Place, South Kensington, Hazel quickly became a well-known figure in London's political, artistic and literary circles. Strikingly beautiful, she became a noted fashion innovator, firstly at the fancy dress balls in vogue before the Great War and later at the tableaux vivants fundraisers for the war effort. Regularly featured in Lady's Pictorial, The Tatler and Vogue, she was the model for a number of photographers including E. O. Hoppé (1878–1972) and Cecil Beaton (1904–1980), and featured in her husband's paintings, among which were many of his finest works. She was a member of the private theatre group, The Plough, which produced Clifford Bax's ‘The sneezing charm’ and other plays between 1917 and 1919. Hazel became known as Lady Lavery when her husband was knighted for his work as a war artist in 1918. She was the confidante of many leading politicians and writers, including Hilaire Belloc, Winston Churchill (to whom she gave painting lessons), Tim Healy (qv), Ramsay MacDonald, George Bernard Shaw (qv), Lytton Strachey and W. B. Yeats (qv). In 1929 she appeared in One family, (as 'Ireland') a film written by J. M. Barrie for the Empire Marketing Board.
In 1916 John Lavery was commissioned to paint the trial of Sir Roger Casement (qv). Painting the portraits of those in the courtroom introduced the Laverys (both supporters of home rule) to prominent Irish political figures, and they became increasingly drawn into Irish political life. Hazel's main contribution to Irish politics occurred when the Laverys’ South Kensington home became an informal meeting place for both sides during the Anglo–Irish treaty negotiations (October to December 1921). Hazel became a conduit for correspondence between Michael Collins (qv) and British politicians, and her close friendship with Collins led to speculation that they were lovers and accusations from some republicans that she had seduced Collins into signing the treaty. Deeply distraught after Collins's death in August 1922, she wore widow's weeds in mourning. She maintained her position as a go-between for members of the newly formed Irish Free State government. Kevin O'Higgins (qv), vice-president and later minister for external affairs was an ardent admirer and close confidant. Her role diminished after O'Higgin's assassination in 1927, but she maintained her interest in Irish affairs and used her social contacts in the campaign to have the paintings of the Hugh Lane (qv) bequest returned to Dublin. When Sir John was invited to design an image for the Irish Free State's banknotes he chose to rework a painting of Hazel as the representation of Cathleen Ní Houlihan, the female personification of Ireland. His painting ‘Killarney’, in which she wears a traditional black shawl and leans on a harp. The whole painting was used on the higher denomination notes; while the head was used for the 10 shilling, £1, and £5 notes. Her image on the new banknotes caused controversy. Regardless, the image remained on Irish notes from 1928 until the £100 note was removed from circulation in 1996 but was retained as the watermark on subsequent notes until 2002. She was a brand ambassador for products such as Ponds Cold Cream and promoted the Armstrong Siddeley motor car. Hazel Lavery died on on 1 January 1935 in London. She and John Lavery had no children together.
Portraits of Hazel Lavery are in many galleries, including Dublin City Gallery, the Hugh Lane, the Laing Gallery, Newcastle-upon-Tyne, the Crawford Municipal Gallery, Cork, the National Gallery of Ireland, the Ulster Museum, the Burns Library, Boston College, and private collections worldwide. Her papers are in a private collection in Ireland.