From his early days in John A. Macdonald’s Kingston law office, Campbell’s cool temper and sharp legal mind led him to a lengthy career in politics. In 1864, he was appointed to the Cabinet of the Province of Canada. He attended the intercolonial conferences at Charlottetown and Québec, and was thus a Father of Confederation. From 1867, he held a seat in the Senate, where he led the Conservatives, and was a minister in the various Macdonald governments. In 1887, he became Lieutenant-Governor of Ontario, holding the post until his death five years later. He lived here in the 1880s.