Francis Henry Portnall was born on the Isle of Wight, England on May 3, 1886. In 1901 he was hired at the architectural firm of William A. Pite in London. Portnall proceeded to article with Pite and Balfour between 1901 and 1905 and then moved to Carlisle, England where he worked as an assistant to James H. Martin dale. In 1906 he emigrated to Canada, settling in Winnipeg, Manitoba where he worked for the firm of Darling and Pearson and was soon sent to Regina to supervise their project for the Knox Metropolitan Church. Upon his return to Winnipeg, he left Darling and Pearson to work for the Winnipeg School Board as an assistant to their chief architect James B. Bitchell. In 1908, Portnall moved to Regina where he first joined the firm of Clemesha and Coltman, and then formed a partnership with Frederick C. Clemesha and established their own firm in 1913. He enlisted in the Canadian Expeditionary Force for World War One, serving with the 10th Brigade Machine Gun Company from 1915 to 1918. Upon his return to Regina, he continued his partnership with Clemesha until 1922 whereupon he established his own business with a focus on the design of educational, ecclesiastical and residential buildings. In 1945 he formed a partnership with Daniel H. Stock, which lasted until 1951, and he began a working relationship with E. Hendrick Grolle.
Portnall died in Regina on September 13, 1976.