Born near Edinburgh, Scotland, Brown emigrated with his father to New York in 1837. In 1843 he moved to Toronto and the following year founded the "the Globe" newspaper which achieved great political influence. Elected to the Legislature as a Reform member in 1851, Brown became a leader of his party in Canada West. In 1858, with A.A. Dorion, he formed a short-lived government. In 1864 he entered the "Great Coalition" government with his adversary, John A. Macdonald, and played a leading part at the Quebec Conference which led to the establishment of the Dominion of Canada on July 1, 1867. Appointed to the Senate in 1873, Brown remained interested in politics until his death.