Studied with Antoine Montfort, Louis Lamotte and Alexander Cabanela. In 1866 was awarded the Rome prize for the painting "Thetis brings to Achilles the arms." Made during a stay in Rome drawings included as illustrations in the published in 1872 a book Francis vey "Rome". Taken in 1868 a trip to Spain reinforced the southern flavor of the works of Regnault; during this trip he painted his famous portrait of General Juan Prim. The next trip, Regnault, in North Africa, gave one of his most famous works, "the Execution without judgment under the Moorish kings of Grenada". In 1870, noted for such films as "Salome" and "Judith and Holofernes", was the most fruitful in the life of the artist. The following year, he went a volunteer in the Franco-Prussian war and was killed at the Battle of Buzenval.