Domat was born at Clermont in Auvergne. He studied the humaniora in Paris, where he befriended Blaise Pascal, and later law at the University of Bourges. Domat closely sympathized with the Port-Royalists, and on Pascal's death he was entrusted with the latter's private papers. After Domat's promotion in 1645, he practised law in Clermont and was appointed a crown prosecutor there in 1655. In 1683, he retired from this office with a pension from Louis XIV to concentrate on his scholarship.
Together with Antoine Dadin de Hauteserre, Antoine Favre and the Godefroy brothers, Domat was one of the few later French scholars of Roman law of international significance. He is principally known from his elaborate legal digest, in three quarto volumes, under the title of Lois civiles dans leur ordre naturel, an undertaking for which Louis XIV settled on him a pension of 2,000 livres. A fourth volume, Le droit public, was published in 1697, a year after his death. After Hugo Doneau's more thorough but less consistent Commentarii iuris civilis, the work was the first of this type of pan-European significance. It was to become one of the principal sources of the ancien droit on which the Napoleonic Code was later founded. Domat's work was in line with earlier Humanist attempts to transform the seemingly random historical sources of law into a rational system of rules. However, as a supporter of a Cartesian juridical order, Domat endeavoured to found all law upon ethical or religious principles, his motto being "L'homme est fait par Dieu et pour Dieu". The work was thus an attempt to establish a system of French law on the basis of moral principles, and it presented the contents of the Corpus Juris Civilis in the form of a new system of natural law. After the work of Robert Joseph Pothier, Domat's work is regarded as the second most important influence on the Civil Code of Lower Canada.
Besides the Lois civiles, Domat prepared, in Latin, a selection of the laws in the Digesta and the Codex Justinianeus under the title Legum delectus ; it was subsequently appended to the Lois civiles. Domat died in Paris on 14 March 1696.
