Born in Moulins in 1584, Dinet joined the Society of Jesus in 1604 and spent his noviciate period in Nancy; he studied philosophy in Pont-à-Mousson and became tutor of poetry and rhetoric at the College of Rouen (1607–10), after which he studied theology at La Flèche, where he was prefect of studies until 1614, at the time when Descartes was a student there. After a year of religious probation in Paris (1614–15), he received various appointments in Jesuit establishments: preacher in Rouen, Blois, Bourges, and Orléans; professor in Rennes, rector of the Colleges of Orléans (1620–23) and Rennes (1628–31); and, later on, provincial of France (1639–42) and of Champagne (1643–47). He was confessor to Louis XIII (March–May 1643) and assisted the king at his deathbed; subsequently he was confessor to young Louis XIV (June–December 1653). He died in Paris in 1653.

Descartes appealed to Dinet in his capacity as provincial of the French Jesuits to arbitrate his polemics with Pierre Bourdin, author of the Seventh Objections (AT III 468), for which Descartes was grateful (“I am much obliged to the R[everend] F[ather] Dinet for the frankness and prudence he made use of on that occasion” [AT III 596]). Descartes also thanked him for his support when, during his voyage to Paris in 1644, Dinet organized a reconciliatory meeting between Descartes and Bourdin (“I know it is you in particular that I owe the happiness of this agreement; and I am therefore particularly indebted to you for it” [AT IV 143]) and in 1644 sent copies of the Principles of Philosophy to Bourdin to circulate among the Jesuits, including Dinet himself (AT IV 143).

It was Dinet whom Descartes chose as witness to his first great polemical writing, Letter to Father Dinet, which was published together with the second edition of the Meditations (a copy of which Huygens already saw on May 26, 1642 [AT III 788]), and in which he compares the “calumnies” of Bourdin to the attacks by Gysbertus Voetius against the Cartesian program of studies at the University of Utrecht.