Born in 1836 in Aberdeen, Scotland, William Clark was educated at Marischal College and the University of Edinburgh. He came to Canada in 1859 and was called to the bar of Upper Canada in 1861. A prominent social activist, he became a bank director and authored a number of articles on travel. In 1866 he married Helen Gordon. Clarke was appointed Lieutenant Governor of Ontario in 1903. He supported education and hospitals during his mandate, and served until 1908. He died in 1917 in Prout's Neck, Maine.