Monin was born at Beauraing in the Duchy of Luxembourg in 1565. He obtained the degree of Licentiate in Sacred Theology, and in 1592 was appointed a canon of Namur cathedral. In 1603 he resigned his canonry and entered the Society of Jesus. He went on to serve as rector of Jesuit colleges in Namur and Liège.
He died 17 September 1624 while serving as spiritual prefect of a Jesuit house in Lille.
- Sacrarium Leodiense (1618)
- Sacrarium perantiqui comitatus Namurcensis (Liège, Jean Ouwerx, 1619)
- "Gillis du Monin", in A. J. van der Aa, Biographisch woordenboek der Nederlanden, vol. 12 (Haarlem, 1869), 982-983.
- Jean-Noël Paquot, Mémoires pour servir à l'histoire littéraire des dix-sept provinces, vol. 6 (Leuven, 1765), 261-262
- Ch. Wilmet, "Fragment d'une histoire ecclésiastique de Namur: Épiscopat des évêques Dauvin et Des Bois", Annales de la Société archéologique de Namur, vol. 8 (1863-1864), 383-424.