Cestac studied at the seminary and was later ordained to the diaconate on 26 June 1825 and ordained to the priesthood on 17 December that same year at the age of 24.
Cestac was cleared for beatification in 2014 after Pope Francis approved a miracle that had been found to have been attributed to his intercession. He was beatified on 31 May 2015 by Cardinal Angelo Amato on behalf of the pope. Born to Dominique Cestac and Jeanne Amitessarobe, he was the siblng of Marianna and Elise.
Father Cestac was later appointed the Vicar of the Cathedral of Bayonne six years later on 27 August 1831 and gave his full attention to the poor and met with them frequently in order to better serve them.
In 1836, he established a home for poor girls in Bayonne. On 6 January 1842, on his birthday, Cestac co-founded the Servants of Mary.
He died in 1868. The cause of beatification for Cestac commenced on 8 April 1908 under Pope Pius X despite the fact that the cause had commenced on a local level in Bayonne in 1898.
This meant that he became a Servant of God. Pope Paul VI declared Cestac to have lived a life of heroic virtue and named him to be Venerable on 13 November 1976.
Pope Francis later approved a decree that recognized a miracle attributed to his intercession on 13 June 2014, thus, clearing Cestac for beatification. He was beatified by Cardinal Angelo Amato on 31 May 2015.