Cartier was born in Saint-Antoine, Quebec (then known as Lower Canada). He studied law and in 1835 worked as a lawyer and also became involved in the railway business. Cartier became active in politics in 1848 when he was first elected He fought with Louis-Joseph Papineau in the Patriotes Rebellion of 1837, and was forced into temporary exile in Vermont. He practised law when he returned and was elected to the Legislative Assembly of the Province of Canada in 1849. In 1852 he supported the creation of the Grand Trunk Railway, and from 1858 to 1862 he served as premier of the united province. He was a loyal and devoted friend of John A. Macdonald, for whom he secured power in lower Canada. In 1864 Cartier and Macdonald joined the Great Coalition with George Brown.
A supporter of the Patriots' movement in 1837, Cartier (1814-1873) rose to prominence in the 1850's as the undisputed leader of the French Canadian Block, renamed the Bleus.
As a delegate to all of the constitutional conferences which led to the passing of the Constitution Act (1867) the presence of Cartier guaranteed that French Canadian rights would be fully protected in the new Confederation by insisting that federalism was the only acceptable system of government to Quebec.