He ran the Bloud et Gay publishing house for many years, and edited the influential journals La Vie Catholique (Catholic Life) and l'Aube (The Dawn).

[1] In 1903, when he was aged 18, Gay helped at the national congress of the Cercles d'études (Study Circles) in Lyon.

[2] He was deeply influenced by Sangnier's views on Social Catholicism, and founded a branch of Le Sillon in Roanne.

He left when the seminary closed in December 1906 and moved to Paris, where he studied at the Sorbonne faculty of letters.

In 1926 La Vie Catholique defended Pope Pius XI's condemnation of the far-right Action Française.

[4] In 1927 Gay founded the Volontaires du Pape (Volunteers of the Pope) to disseminate Social Catholicism throughout Europe, and arranged a large pilgrimage to Rome with this organization in 1929.

[4] In 1938 Gay and Bidault, who also belonged to the PDP, founded the New French Team (Nouvelles Equipes Françaises, NEF).

[1] Francisque Gay became active in the French Resistance, using the Lyon and Paris premises of his publishing house as a base.

In November 1944 Gay, Georges Bidault and others founded the Popular Republican Movement (Mouvement Républicain Populaire, MRP).

Also in November 1944 Gay was appointed to the Provisional Consultative Assembly and was made a member of the committees on National Education and on Information and Propaganda.

He was reelected to the second National Constituent Assembly and voted for the draft constitution of 28 September 1946, which was ratified by a popular referendum.