Born Henryville, Quebec in 1905, the son of Arthur Pigeon and Maria Demers, he studied at Université Laval and obtained an LL.L in 1928. Called to the bar that year, he settled in Quebec City and practised law with St-Laurent, Gagné, Devlin et Taschereau.
In 1940 he became law clerk of the Quebec Legislature, a position he held for four years before joining the law firm of Germain, Lapointe, Thibaudeau et Roberge. He taught constitutional law part-time at Université Laval for 15 years and was chairman of the National Council on the Administration of Justice from 1963 to 1967. His teaching notes are archived under the title "Cours de droit constitutionnel : Notes de cours de Mtre Louis-Ph. Pigeon" at the Bibliothèque et archives nationales du Québec under call number 342.71 P623c in the "Iris" Catalog: http://iris.banq.qc.ca/iris.aspx.
Louis-Philippe Pigeon is noted among jurists for his book on statutory interpretation entitled Rédaction et interprétation des lois, published in French by the Queen's Printer for Quebec's Ministère des communications in 1965 (ISBN 2551088208), and in English under the title Drafting and Interpreting Legislation by Carswell Toronto in 1988 (ISBN 0459321617). Both titles can be found in the aforesaid Iris catalog.
Maître Pigeon also acted as a legal adviser to the Premier of Quebec, Jean Lesage, from 1960 to 1966. On September 21, 1967, Pigeon was appointed to the Supreme Court of Canada. He served on the Court for 12 years and retired on February 8, 1980. Justice Pigeon died on February 23, 1986, at the age of 81.