Jacques was born in Normandy (France) in 1803. His father was a prosperous farmer. His mother died when he was 7, but not before she had given him striking example of generosity to the poor. In his later missionary work in Mauritius, Jacques was guided by the formula: "Succeed in having good parents and you will have good children." From his own parents, he inherited a vigorous Christianity that was direct and daring. As a boy, he said he would like to be a priest or a doctor. In Paris in 1830, he qualified as a doctor.
When he returned to Normandy to set up medical practise, there was a noticeable change in his behaviour. Handsome, successful, a skilled horseman, he was much in demand at fashionable gatherings. He became immersed in the social scene and abandoned the practise of his religion. A series of events culminating in a brush with death when he fell from his horse led him to completely re-examine his life. A few months later, he entered the seminary and within four years he was ordained a priest. After two years as a parish priest in Normandy, he handed over all his possessions to Francis Libermann, leader of the missionary Society of the Holy Heart of Mary (which fused with the Congregation of the Holy Ghost in 1848) and left for Mauritius.
In Mauritius, the slaves had recently been liberated. Among them Jacques was to spend the last 23 years of his life without ever seeing his native France again. He immediately set up a Mission for the Blacks. His heart went out to these people, now free but still treated as inferior. To get to know them, he learned their language. To be like them, he fasted every day and slept on a bed made from a wooden packing case. He refused to accept the common opinion that regarded them with contempt. He tried to awaken them to their personal worth by telling them of God's great love for each of them. He made considerable demands on them. He tested them and then he trusted them. He gave them responsibility for the animation and instruction of small groups. What started in the city of Port Louis spread across the island. A new enthusiasm for the Church was underway.
As a doctor, Jacques was known as a friend of the poor. At the seminary, he became a man of prayer. Now he had become one of the poor. In long hours of prayer, God came close to him. He guided and strengthened him, He gave him the courage to continue to trust the people and so become the "Apostle of Mauritius".