David Mills was born in Palmyra, Orford Township, in southwestern Ontario, on March 18, 1831, the child of Nathaniel Mills, one of the first settlers in the area, whose farm was on lot 70, on Talbot Road (now King's highway 3), just north of Lake Erie and west of Clearville. After being educated at the University of Michigan, Mills became superintendent of schools for Kent Country from 1856 to 1865. In December 1860 he married M. J. Brown, the "Mary" to whom he addresses "I Feel I'm Growing Old" thirty-eight years later. He embarked then on a public career by publishing The Present and Future Political Aspects of Canada (1860) and next The Blunders of the Dominion Government in connection with the North-West Territory (1871). Mills was elected as a Liberal to the Parliament of Canada for the Electoral Division of Bothwell from 1872 to 1878 and again in 1887. During this period, 1876-78, he was appointed Minister of the Interior, and a member of the Privy Council. During a period out of office, in 1883, he was called to the Ontario Bar. This enabled him to serve as legal counsel before the Privy Council in 1884 on defining the north-west boundary of Ontario. Ontario made him Queen's Council in 1890. Mills was appointed to the Canadian Senate in 1896 after failing to win election. He died in 1903.

• Gemmill, John Alexander. The Canadian Parliamentary Companion, 1897. Ottawa: J. Durie, 1897. 79-80. CIHM 32962
• Hodges, Joyce. "Orford Township, Kent County, Ontario, Canada."
• Vipond, Robert C. "Mills, David." Dictionary of Canadian Biography Online. 1901-1910 (Volume XIII). University of Toronto / Université Laval, 2000.