Louis Joseph François was born 3 February 1751 in Busigny, France. He entered the seminary of the Congregation of the Mission with Jean-Jacques Dubois, also of Busigny, on 4 October 1766 when he was fifteen and a half years old. He took vows at age 18. The date of his ordination is unknown.
Following ordination Louis worked in the seminary for 18 years, until 1781. During that year he was superior of the seminary at Troyes. He was appointed Secretary General by the Superior General, Antoine Jacquier, in 1786.
Known as a gifted preacher, he was invited to give important sermons, including the eulogies of Madame de Maintenon, 26 July 1786, and Madame Louise de France, a Carmelite and daughter of Louis XV, 15 April 1788. He also gave retreats for clergy and spoke at the Tuesday Conferences at Saint Lazare.
Following Jean-Félix-Joseph Cayla de la Garde's election as Superior General in 1788, François was sent to Saint Firmin, where there was a seminary and where the superior had just died. His responsibilities there included overseeing repair of buildings, increasing the number of students, and building resources to ensure the financial future of the seminary.
While Louis was at Saint Lazare on Sunday, 13 July 1789, the premises were sacked by the French revolutionaries. He, Cayla, and two others escaped. Following the sacking, no further support was provided by the motherhouse for the seminary. As a result, Louis had only student fees and income from rental properties to fund operations at Saint Firmin. Debt grew despite an increasingly austere budget. The onset of the Revolution completely compromised attempts at fundraising.
The revolutionaries set in place a practice of requiring clergy to swear an oath of fidelity to revolutionary principals. After studying the situation, in January 1791 Louis published the word for which he is best known, Mon Apologie. In this and the great number of subsequent pamphlets he published, he explained his implacable objections to the oath required by the Civil Constitution of the Clergy. Mon Apologie, which was reprinted seven times, concludes: “To die of hunger is an evil, but there is a greater unhappiness living as an apostate or unfaithful to one’s religion.”
The anonymous publication of his pamphlets did not prevent Louis from being identified as their author. In consequence, he became famous for authoring pamphlets on subjects as diverse as the Civil Constitution and the pretensions of the bishop of Gratien, who had been put in place by mechanisms of the Civil Constitution.
Massacre of clergy in Paris began in the abbey of Saint Germain des Prés on the afternoon of 2 September 1791. By 5:30 AM the next morning, Sunday, a mob had arrived at Saint Firmin and invaded the premises. Some priests were killed brutally in the courtyard; others were killed in the building. Nicolas Gaumer, a Vincentian, tried unsuccessfully to warn Louis; when he could not, he escaped by climbing over a back wall of Saint Firmin.
Louis and two others were flung to the ground from third floor windows. With bats (implements used to stir and harden plaster), women beat them to death.