Evans was born in Spencerville, Ontario, the son of Rev. J.S. Evans and Mary Jane Vaux. He was educated at the Collegiate Institute in Hamilton, Ontario, Victoria University and Columbia University. He subsequently moved to Manitoba.
Evans was active in the publishing industry of his new province, founding the Winnipeg Telegram and writing a book on Canadian Imperialism during the Second Boer War. In 1920, he co-founded a publishing firm specializing in grain industry news. He married Mary Irene Gurney, a noted pianist, in 1900.
Evans was first elected to the Manitoba legislature in 1922, leading the Conservative party list in Winnipeg (which elected ten MLAs through preferential balloting). He was re-elected in 1927 and 1932, topping the Winnipeg ballot on the latter occasion. Evans was chosen as Conservative party parliamentary leader following the resignation of Col. Fawcett Taylor in 1933. He did not run against Errick F. Willis for the party leadership in 1936 and did not run for reelection in the provincial election which followed.
In 1931, while still serving in the Manitoba legislature, Evans was appointed by British Columbia Premier Simon F. Tolmie to head a commission investigating that province's fruit-growing cooperatives. The commission's report recommended a return to open competition and was opposed by many within the industry.
Evans continued to publish grain industry news following his retirement from parliament. He died in 1949.
Notably, Evans's brother Harry M.E. Evans served as Mayor of Edmonton, Alberta. As well, Evans's son Gurney Evans served as a cabinet minister in the governments of Dufferin Roblin and Walter Weir in Manitoba.
- "William Sanford Evans (1869-1949)". Memorable Manitobans. Manitoba Historical Society.
- Bumsted, J M (1999). Dictionary of Manitoba Biography. University of Manitoba Press. p. 78. ISBN 0887551696. Retrieved 2013-01-31.
- McCrea, Walter Jackson (1925). Pioneers and prominent people in Manitoba. pp. 173–74. Retrieved 2013-01-31.
- Canadian Press Association (1911). Who's who in western Canada. p. 171. Retrieved 2013-01-31.
- "Mayors, Past and Present". City of Winnipeg. Archived from the original on 2008-12-25. Retrieved 2013-01-31.
- "MLA Biographies - Deceased". Legislative Assembly of Manitoba. Archived from the original on 2014-04-07.
- "W. Sanford Evans and the Canadian Club of Winnipeg, 1904-1919". Manitoba History. Manitoba Historical Society. Retrieved 2013-01-31.