The descendant of a seigniorial family, François de Laval was born on April 30, 1623 in Montigny-sur-Avre, in the diocese of Chartres, France. He studied with the Jesuits at La Flèche College, where his interest for the missions in Canada blossomed. He continued his studies in Paris at Clermont College. Upon his father’s death and that of his two elder brothers, he assumed the management of his family’s estate, of which he became heir. He was ordained a priest in 1647. He strove for spiritual perfection, caring for the sick and overseeing the education of abandoned children. Named archdeacon of the diocese of Évreux, he visited over 150 parishes, reforming them according to the spirit of the Council of Trent. In 1653, after the failure of a missionary endeavour in Tonkin, Vietnam, he resigned from the archdiaconate of Évreux and renounced the pension to which he was entitled, ceding to his brother his inheritance and his rights as heir. He departed for Caen, where he lived at the hermitage of Jean de Bernières, one of the great mystics of his time. Joining works of charity to his life of prayer, he oversaw, during this period, the reform of a monastery and the affairs of a community of Hospitallers (a female religious congregation founded in La Flèche, France in 1636).

On June 3, 1658, François de Laval was named Apostolic Vicar to Canada, against the ambitions of the archbishop of Rouen who wanted to extend his own jurisdiction to New France. He was consecrated a Bishop in secret in Paris on December 8 and arrived in Québec on June 16, 1659. Taking charge of the colony which numbered only 5 parishes and less than 2,500 inhabitants, he had to impose his authority against the Archbishop of Rouen who wished to promote the superior of the Priests of the Society of Saint Suplice in Montreal, and also against the promoters of Gallicanism in one part of the colony. He also faced certain challenges with the governors: quarrels over precedence, but most of all, his opposition to the trafficking of eau de vie among Indigenous Peoples, which was a source of revenue for the colony but also of murder, rape, and other acts of violence.

In 1663, Bishop de Laval founded the Major Seminary of Québec, destined to be the heart of the Church of Canada. The Seminary served as a place of formation for priests, a centre of affiliation for clerics, the diocesan chapter, a distribution centre for tithes, and a select place from which the bishop could “draw pious subjects […] to send them […] into parishes […] in order to exercise pastoral functions there.” In 1668, Bishop de Laval founded a minor seminary and, later, an arts and trades school. Named Bishop of Québec by Louis XIV in 1663, de Laval was confirmed in this function by Rome in 1674.

Bishop de Laval dedicated significant sums of money to help the poor and to educate children. He administered the Sacrament of Confirmation to the colonial settlers and to the local Indigenous population and encouraged the faithful to establish pious societies. In 1681, he undertook his final pastoral visit and in 1684 he submitted his resignation.

During his 25 years in New France, the number of parishes went from 5 to 15, the number of priests from 25 to 102, and the number of women religious from 32 to 97; 13 priests and 50 women religious were natives of the diocese of Québec. Returning to Québec in 1688, Bishop de Laval retired at the Seminary. He devoted himself to prayer and caring for the poor. Despite his illness, he replaced his successor during his absences and died while exercising his functions on May 6, 1708. He was proclaimed Blessed by John Paul II on June 22, 1980 and was canonized by a decree of Pope Francis on April 3, 2014.