William Edward Simpson, 1894-1988, was born in Wardsville, Ontario and moved to Lethbridge, Alberta in 1910. He read law in a local law firm and graduated from the University of Alberta in 1918. He established the firm of Simpson and Van Allen (later Simpson and Macleod) in Edmonton and became a K.C. in 1938. Much of the firm's work dealt with the petroleum industry.
Simpson participated in three royal commissions including the Rowell-Sirois Commission in 1937 for which he helped prepare The Case for Alberta. He was also counsel for Alberta in the preparation of its brief to the Royal Commission on Economic Prospects (Gordon Commission) in 1955 and was joint counsel for Alberta in preparing the brief presented to the Royal Grain Inquiry Commission (Turgeon Commission) in 1924.
He and his wife, Ethel Lillian Stewart, were married in 1916 and had five children, David, ?-1941, William, Lenna (Manly), Kathleen (Guinness), and Jocelyn (McCreedy).