Gibieuf studied at the Sorbonne and received the title of doctor in theology in 1612. The same year he joined the Oratory, recently founded by Cardinal Pierre de Bérulle. He quickly became Bérulle's right-hand man and played an important role in the expansion of the Oratory (see Oratorian). However, because of internal dissent, he was not elected superior of the congregation at Bérulle's death (1629). From 1631 on, he was kept out of its leadership, for about ten years. He nevertheless remained in charge of the supervision of the Carmelites.

Through Bérulle, Gibieuf associated with Descartes in Paris between 1626 and 1628. After Descartes’ departure for the Netherlands, they remained on excellent terms. Gibieuf interceded on Descartes’ behalf with the Sorbonne to obtain an approbation of the Meditations.

Gibieuf and Descartes share some views on divine and human freedom. As Bérulle's disciple, Gibieuf defended, in his On the Liberty of God and of the Creatures, the “Augustinian” thesis of the necessity and invincibility of grace, against the “Molinist” theory that “indifference” is essential to human free will. For the Jesuit Molina, our will is not free if it cannot choose one of two opposite alternatives indifferently, that is, without being irresistibly inclined to one of these opposites. In contrast, for Gibieuf, inclination is compatible with free will because it is not an external constraint. Indifference is proper only to God's supreme freedom. Because of his “amplitude” – namely, his infinity, inexhaustible power, and absolute perfection – God is not limited or constrained in any way regarding his ends or means. On the other hand, in the case of humans, indifference characterizes a will that has gone astray from the path marked by God. Creatures are essentially ordained to God as their end, and human freedom is perfectly achieved in the adhesion to the motion that irresistibly draws us back to God.