Painter and printmaker John Robert Keitley Duff was born in Hackney, London on January 22, 1862, the son of Robert Duff, a watch manufacturer in London, and his Scottish-born wife Janet. Robert Duff died in 1871 and Janet raised John Robert with the help of her live-in maid, Emily Robertson. Duff was educated at Bishops Stortford, Hertfordshire and after graduation decided to pursue law, entering Sidney Sussex College, Cambridge in 1884, graduating B.A. and LL.B. in 1887 and M.A. in 1891.

In 1891, then a 29-year-old barrister-at-law living at Sunny Gardens, Hendon, he took up art studies at the Slade School under Alphonse Legros (1837-1911). Records show that he married in 1892 to Emma Louise Clark and, in 1911, was listed as a 49-year-old painter living at 100 Sunningdale Road, Hendon with his wife and four children. A painter in oils and watercolors as well as a pastelist and etcher, he often featured pastoral scenes with farm animals or birds, though he also focused on architecture.

Duff exhibited at the Royal Academy from 1891-1925 and with the New English Art Club beginning in 1894, and was elected a member of the Royal Institute of Painters in Watercolours in 1913 and of the Royal Society of Etchers in 1919. International participation included shows in Budapest (1910) and Venice (1912). A solo exhibition was held at the Goupil Gallery from February through March of 1913. Shortly before his death he donated a quantity of his watercolours, pastels, etchings, and enamels to the Southwold Museum in Suffolk and others to Hendon Central Library. John Robert Keitley Duff died at 'Oakview', 100 Sunningdale Road, Hendon, on 26 September 1938, aged 76.

Works by Duff can be found in the collections of the British Museum, London; the Victoria & Albert Museum, London; Christchurch Art Gallery, New Zealand; the Center for Australian Art; and the Smithsonian American Art Museum, USA.

Information partially sourced from suffolkartists.co.uk