[2] Walter arrived in South Australia in the William Barras in December 1839.

[1] His first occupation was as manager for fellow-passenger Jacob Hagen's estate at Echunga, where his wine was some of the first produced in the colony.

[1] He started business in Gawler as a flour miller ("The Victoria Steam Flour Mill", founded by Stephen King JP) and merchant in September 1847,[4] and, in conjunction with Harrold Brothers as Duffield, Harrold and Company (later Duffield, Harrold and Hurd), owned Weinteriga and Outalpa stations.

[5] Duffield was member for Barossa in the South Australian House of Assembly from 9 March 1857 to 6 April 1868 and from 14 April 1870 to 13 December 1871,[6] and was Treasurer in the John Hart Government from 23 October 1865 to March 1866,[7] and in the Ministry of James Boucaut, which succeeded it, from the latter date till 3 May 1867.

[6] Duffield died in Gawler on 5 November 1882 and was buried in Willaston General Cemetery.