As a member of the Great Coalition, Hector-Louis Langevin attended all three conferences leading to Confederation in 1867 and helped to draft the text of the constitution. On George-Étienne Cartier's death in 1873, Langevin became leader of the Quebec branch of the Conservative Party.
Langevin, an attorney, articled with Augustin-Norbert Morin and George-Étienne Cartier. His first steps in an active political life were at the municipal level. In 1856, he was elected to the Municipal Council of Québec City and was mayor of the city from 1858 to 1861. He made the jump to Canadian politics in 1857, when he was elected in the riding of Dorchester. He joined the Cabinet as solicitor general in 1864 and held the office until 1866, when he became postmaster general.
In 1867, Langevin became secretary of state and superintendent general of Indian affairs. In 1869, John A. Macdonald made him minister of public works. Compromised by the Canadian Pacific scandal, which forced John A. Macdonald's government to resign in 1873, Langevin left politics until 1876. When John A. Macdonald was re-elected prime minister in 1876, he reinstalled Langevin at the Post Office Department until 1879. Langevin also became minister of public works again. Throughout the 1880s, Langevin remained John A. Macdonald's right-hand man in Quebec, but conflicts within the Conservative Party undermined his influence. Louis-Rodrigue Masson, the new leader of the Quebec Liberal Party, and Joseph-Adolphe Chapleau attempted, with some success, to discredit him.
When Louis Riel was hanged, Hector-Louis Langevin was one of the few Conservatives to survive the 1887 elections in Quebec. Despite the views of certain politicians, he remained the minister of public works. Prime Minister John Joseph Caldwell Abbott then went back on his promise to appoint Langevin lieutenant-governor of Quebec. Langevin left politics in 1896.
Désilets, Andrée. "Langevin, sir Hector-Louis." Dictionnaire biographique du Canada. Vol. XIII. Québec : Presses de l'Université Laval, 1983. P. 617-622.