After he was a professor of history in 1976 at the secondary level, he entered higher education in 1989 as an attaché temporaire d'enseignement et de recherche at the University of Maine.
In 1991, in Sorbonne, he defended his Ph.D. thesis under the direction of Charles Pietri, the then director of the École française de Rome: Maladies, malades et thérapeutes en Gaule du IIIe au VIe.
In the course of his research, he conceived the neologism "nosomonde" to designate the perception of the world by Christians - in this case [Stoicism|Stoicians] - of late antiquity as intrinsically ill.
With Benoît Jeanjean, Bertrand Lançon is at the origin of the French translation of the "Chronique" of Jerome, first part of Chroniques latines de l'Antiquité tardive et du haut Moyen Âge[2] whose translation and commentary were provided by the study group set up in Brest in 1998 with Hervé Oudart, the Gestiat (Groupe d'études sur les sources textuelles et iconographiques de l'Antiquité tardive), followed in 2013/2014y by volume 2 of these chronicles, those of Marcellinus d'Illyricum (379-534).
In 2006, Bertrand Lançon also began publishing a series of novels entitled Les Enquêtes de Festus, whose main character is a Roman investigator of the generation of Augustine of Hippo.