Sir John Alexander Macdonald, GCB, KCMG, PC, PC (Can), QC (11 January 1815 – 6 June 1891), was the first Prime Minister of Canada. The dominant figure of Canadian Confederation, his political career spanned almost half a century. Macdonald served 19 years as Canadian Prime Minister; only William Lyon Mackenzie King served longer.

Macdonald was born in Scotland; when he was a boy his family emigrated to Kingston, Upper Canada (today in eastern Ontario). He articled with a local lawyer, who died before Macdonald qualified, and Macdonald opened his own practice, although not yet entitled to do so. He was involved in several high-profile cases and quickly became prominent in Kingston, which enabled him to seek and obtain a legislative seat in 1844. He served in the legislature of the colonial Province of Canada and by 1857 had become premier under the colony's unstable political system.

When in 1864 no party proved capable of governing for long, Macdonald agreed to a proposal from his political rival, George Brown, that the parties unite in a Great Coalition to seek federation and political reform. Macdonald was the leading figure in the subsequent discussions and conferences, which resulted in the British North America Act and the birth of Canada as a nation on 1 July 1867.