Courtois was internationally famous as a painter of battle scenes. Called Le Bourguignon, Il Borgognone, Giacomo Borgognone and Giacomo Cortese; born on 12 February 1621 in Saint-Hippolyte (Franche-Comté), the son of Jean-Pierre Courtois under whom he first studied. In 1636 he went to Italy and followed the Spanish army in Milan 1636-1639, and proceeded to Bologna (where he met Reni and Albani), Florence and Siena, before reaching Rome c. 1640. In Rome, he obtained the patronage of important noble families. 1651-1655 he worked for the Medici in Florence. After a stay in Frnache-Comté he was back in Rome in 1657. In 1657, following the death of his wife (whom he was thought to have murdered) he became a Jesuit and there is a brooding Self-portrait in the Uffizi. He died in Rome.
Although he painted landscapes (which had been admired by Reni) and some religious frescoes, he became known above all for his battle scenes, in which he introduced an element of involvement, then quite new. In Rome he knew Pietro da Cortona, Pieter van Laer and Michelangelo Cerquozzi, and his work compares in some respects with that of Salvator Rosa.