He studied under his father, the painter Jean-Baptiste van Loo, at Turin and Rome, and he won a prize at the Académie Royale de Peinture et de Sculpture in Paris in 1725. With his uncle, the painter Charles-André van Loo, he went to Rome in 1727–1732, and in 1736 he became court painter to Philip V of Spain at Madrid, where he was a founder-member of the Academy in 1752. He returned to Paris in 1753, and painted many portraits of Louis XV of France. In 1765 he succeeded Charles-André as director of the special school of the French academy known as the École Royale des Élèves Protégés. In 1766 he made the portrait of the Portuguese statesman Sebastião de Melo, Marquis of Pombal.