William Blackwood Sanders was born on 17 April 1875, the fourth of seven children. His parents were James Carstairs Sanders and Emma Harriet, who married in October, 1869. James Carstairs sailed to Adelaide from Leith, Scotland, with his parents and siblings in 1838. Emma Harriet was the oldest daughter of RA McKinley of Pandanus Creek Station in Queensland.

William Blackwood's grandfather, also named William Sanders, became a prominent businessman and pastoralist after his arrival in Adelaide in 1838, and he was elected to the first Adelaide City Council in 1840. After returning to Australia from Edinburgh, where he finished his education in the early 1850s, James Carstairs Sanders began working in the pastoral industry and he and his brother, Robert, purchased Craigee Station in Dalrymple, Queensland, in 1861.

James and his family moved to Warcowie sheep station in South Australia some time after it was purchased by his father in 1873. William Blackwood Sanders was born on Warcowie in 1875. Little detail about William Blackwood’s early life and education is available, but he studied wool classing at the South Australian School of Mines and Industry in 1901 and 1902, and subsequently gained employment at Nanutarra and Cooya Pooya sheep stations in north-west Western Australia. He went on to work as a supervisor and wool classer at various sheep stations, including Erudina and Mount Cone stations in South Australia.

In 1914 WB Sanders married Eva Lyle Jenkins. They had two sons: James Blackwood, who was born in March 1915, and William Ferguson Blackwood, born in 1917.

In 1944 William Blackwood Sanders wrote ‘William Sanders and some "Canowie" History - compiled by WB Sanders - a grandson - 16 November 1944’.

WB Sanders donated a number of photographs and objects from Western Australia and South Australia to the South Australian Museum in the late 1940s and early 1950s.