While director of "La Solitude", he wrote several ascetic and biographical works and collected materials for future publications.
Two subsequent voyages to Canada enabled him to write several important biographies, those of Sister Marguerite Bourgeoys, of Jeanne Mance (with the history of the Hôtel-Dieu, Ville-Marie), of Marie-Marguerite d'Youville, and of Jeanne Le Ber.
His chief works relating to Old France are his life of Jean-Jacques Olier and Monuments inédits sur l'apostolat de Sainte Marie-Madeleine en Provence.
On the other hand, he has been credited for giving prominence to persons and events of Ville-Marie, less elaborately treated by the Jesuit "Relations" and later histories.
Several places in the province of Quebec, in Canada, are named after Étienne-Michel Faillon.