Marie-Théophile was born at Rochefort, the middle child of the three sons of Joseph Jean Baptiste Alexandre Griffon du Bellay and Marie Elisabeth Claire de Nesmond.

His father was one of the last remaining survivors of the infamous wreck of the Medusa (upon which he had served as secretary to the then governor of Senegal Colonel Julien-Désiré Schmaltz) and became a commissioner in the French Navy.

[1] In June of the year 1862, by order of the Minister for the Navy, Griffon du Bellay was dispatched, aboard the naval vessel Pionnier and in the company of ship's lieutenant Paul Augustin Serval, to explore the Ogooué delta.

In December 1862, the two explorers organised a second expedition, setting off on a whaling boat with the objective of finding a passage between the Gabon estuary and the Ogooué via the river Remboué, in the course of which they were able to reach a village in the neighbourhood of Lambaréné in what is now Moyen-Ogooué Province.

[1] Still unwell, since falling ill earlier in the year, Griffon du Bellay was forced to abandon the attempt, while Serval pushed on alone and, with some difficulty was finally able to reach the village of Orongo, inhabited by the Enenga people (a subgroup of the speakers of Myènè), whose King, Rempolé, accorded him, much to his relief, a warm welcome.

Most notable among these were the powerful stimulant and hallucinogen Tabernanthe iboga (family Apocynaceae),[3] used in the indigenous Bwiti religion,[4] and the legume Griffonia simplicifolia, which is rich in the serotonin precursor 5-HTP.