Sir Alexander Tilloch Galt was born on September 6, 1817, in Chelsea, London, England.

He was a politician and one of the fathers of the Canadian Confederation. He was educated at Reading School, England. Between 1864 and 1867, he was a member of the Great Coalition government in the Province of Canada that secured Confederation in 1867. He served as an Inspector-General of Canada. He was a Member of the Canadian Parliament for Sherbrooke (1867–1872) and the 1st Canadian Minister of Finance (July 1- November 7, 1867). In 1877, the British appointed him as their representative in the Halifax Fisheries Commission concerning American fishing rights in Canadian waters. He also became the 1st Canadian High Commissioner to the United Kingdom (1880-1883). In 1882, with his son Elliot, he established the Alberta Railway and Coal Company to build two narrow-gauge rail lines and create a coal mining industry that could bring settlers to the Northwest Territories. He has a street named after him, Avenue Galt in the borough of Verdun, Quebec, in the city of Montreal where he owned lands. In Sherbrooke, Quebec, he has two streets named after him, rue Galt Est/Ouest and rue Alexandre. The Galt Gardens public park and Galt Museum (formerly a hospital) in Lethbridge, Alberta, are named after him.

In 1848, he married Elliott Torrance (1828–1850) and in 1852, he married her sister Amy Gordon Torrance (1834–1911). He died on September 19, 1893, in Montreal, Quebec.