Painter and etcher of diverse subjects. Famed for his urban and domestic interiors, especially of theatres and of Camden Town. He was influenced by the modern life subjects of Degas and the low tonality of Whistler. He had an abiding interest in popular culture, making the music-hall a special theme and later in his career he adapted nineteenth-century engravings or modern photographs as his source. In the 1900s adopting a thicker, more mosaic-like application of paint, Sickert habitually organised compositions by means of a squared grid.

Born in Munich, the son of O A Sickert, a German/Danish painter who had studied under Couture, the family moved to England in 1868. Studying at King's College, London, Sickert spent three years on the stage 1877-81. In 1881 he enrolled for a year's course at the Slade School under Legros. Striking up a close association with Whistler he worked as the latter's studio assistant. In Paris in 1883 he first met Degas, whose work profoundly influenced his development. From 1885 to 1922 Sickert lived part of virtually every year in Dieppe, being resident there permanently from 1899 to 1905 and 1919-1922.

In 1895 he visited Venice and worked there regularly from 1900 to 1904. Settling in Fitzroy Street, London, Sickert became renowned among younger painters for his authority and knowledge of French painting. Sickert was thus the impetus behind the formation of many important artistic associations: the Fitzroy Street Group, 1907; the AAA, 1908; the Camden Town Group, 1911; and the London Group, 1913. An organiser of the London Impressionists exhibition in 1889, he was elected a member of the NEAC and Society of British Artists in the 1880s. Exhibiting widely in London he showed in Paris and Brussels (Les XX, 1887). A writer of art criticism, he taught at several private schools from 1893 to 1923, and at Westminster School of Art, 1908-1912 and 1915-1918. Working in Brighton and Bath, he left London in 1934 for Thanet, finally settling at Bathampton where he died. He was married for the third time in 1926.