Regnault was born in Paris, and began life at sea in a merchant vessel. At the age of fifteen his talent attracted attention, and he was sent to Italy by M. de Monval under the care of Bardin. After his return to Paris, Regnault, in 1776, obtained the Grand Prix, and in 1783 he was elected Academician. His diploma picture, the "Education of Achilles by Chiron", is now in the Louvre, as also the "Christ taken down from the Cross", originally executed for the royal chapel at Fontainebleau, and two minor works - the "Origin of Painting" and "Pygmalion praying Venus to give Life to his Statue".
Besides various small pictures and allegorical subjects, Regnault was also the author of many large historical paintings; and his school, which reckoned amongst its chief attendants Guérin, Crepin, Lafitte, Blondel, Robert Lefevre, Henriette Lorimier and Menjaud, was for a long while the rival in influence of that of David.