Thomas D. Harrison was born September 19, 1835 in Nelson township, Halton County, Ontario, son of Henry Harrison of England, and Catharine Douglass of New York State. He followed his father’s trade as a carriage maker for many years, employing several men in his prosperous shop near Milton. He served as a justice of peace. He married Elizabeth Smith, daughter of John Durlin Smith and Margaret Book Walker of Palermo, Ontario. About 1883 he went to Manitoba as part of a colonization project, taking up land near Birtle, some 250 miles northwest of Winnipeg and returned there again three years later, but he did not remain there. He lived in Hamilton, Ontario, in his later years, and was on a visit to his son, Wick, in nearby Dundas when he died July 26, 1898. He was buried in Milton at the old family burying ground, now called the Milton Pioneer cemetery.

Thomas D. and Elizabeth Harrison had four sons and three daughters: Ida (mar. Kirkby Townsend), Emma (mar. Broome Smith), Thomas, John, Olivia (mar. Joseph Roseveare), Henry Wycliffe, and Margaret Blanch (mar. John MacKinnon)