Condren was born December 15, 1588, in Vauxbuin, near Soissons. His father, governor of the royal castle of Piles near Meaux, had converted from Protestantism to Catholicism. Charles had a decisive spiritual experience at the age of eleven and half. He studied in the secondary school of Harcourt from 1603 till 1605, but because of an illness returned to his family for several months. He continued his studies at the Sorbonne and was ordained to the priesthood in 1614, receiving his doctorate from the Sorbonne the next year. He gave up his family inheritance, which by the law of primogeniture was his, and entered the house of the French Oratory founded by the Abbé (later Cardinal) Pierre de Bérulle on the Rue Saint-Honoré in Paris, having thought before that of becoming a Capuchin friar.
The next year Condren participated in the foundation of a new house of the Oratory in Nevers and in 1619 was in Langres for the opening of a seminary, in conformity to the decrees of the Council of Trent. He returned to Paris in 1620 to open a new house of the Oratory in Poitiers and in 1624, one at the former Abbey of St. Magloire, which doubled as a seminary.
In 1625, he returned to the house in the Rue de Saint-Honoré. In 1627, he became the confessor of Prince Gaston of France, (Monsieur), brother of King Louis XIII of France. He brought about a reconciliation between the king and his brother, who had been estranged, on April 18, 1630 in Troyes. Condren also bore the responsibility of being the confessor of Bérulle.
After Bérulle's death in 1629, Condren succeeded him as Superior General of the Oratory. Condren was elected very quickly to avoid intervention by Cardinal Richelieu.
The Oratory had 71 houses in 1631, but Condren was discouraged and came near to resigning in 1634. In 1638 he created the College of Juilly, where, at his death, he was laid to rest in the chapel, next to the tomb of Cardinal Bérulle. His first biography was published in 1643 by a member of the French Oratory, Denis Amelote (reviewed in 1657).