Louis-Nazaire Bégin was born in Saint-Joseph-de-la-Pointe-Lévis (now part of Lévis), Quebec, to a family of farmers whose ancestors came from Normandy, France, to Canada in 1655.

Upon his return to Canada, he was named professor of dogmatic theology and of ecclesiastical history at the Seminary of Quebec in July 1868, remaining in those posts until 1884.

Bégin took several months for rest and recuperation from the end of 1883 to the beginning of 1884, and acted as the private secretary to Cardinal Elzéar-Alexandre Taschereau on his tour in Europe from April to December 1884.

He received his episcopal consecration on the following October 28 from Cardinal Taschereau, with Bishops Louis-François Richer dit Laflèche and Jean-François Laforce-Langevin serving as co-consecrators, in the metropolitan cathedral-basilica of Quebec.

Illness forced Cardinal Taschereau to delegate his workload to Bégin, who was made Apostolic Administrator of Quebec on September 3, 1894.

As archbishop, he made vehement condemnations of modernism, jazz music, dancing, and cinemas (which he described as offering "serious dangers, if not approximate occasions, of mortal sin"), the clandestine sale of liquours[2] and the frivolous fashions of women.