Henri Le Floch was born on 6 June 1862 in Caouet in the commune of Plonévez-Porzay, now in Kerlaz, in Brittany. He said he modeled himself on relatives who had remained faithful priests during the French Revolution.
In 1875 he entered the Petit Séminaire de Pont-Croix and in 1878 the Petit Scolasticat de Langonnet, run by the Holy Ghost Fathers (Spiritans). In 1882 he continued his studies at the Grand Scolasticat in Chevilly.