Son of the portrait painter Jean Clouet whose diminutive-name Janet passed to him as a patronym. The leading portrait painter of the mid-sixteenth century in France, he ran a large workshop to meet the demand for his elegant, courtly portraits in Renaissance style. His artistic models were mainly Florentine amd Netherlandish.
He succeeded his father as painter to the King in 1540, retaining the position under François I and Henri II, and he received many commissions during the regency of Cathérine de Médicis, although court commissions seem to have gone increasingly to other painters as well. His oeuvre as a painter and as a draughtsman is considerable. Because of the enormous output and a large workshop, his work is surrounded by questions of attribution that have not been fully resolved. His portrait drawings in the Cabinet des Estampes and at Chantilly serve to identify many of his portraits in oil, and he also practised in miniature. He died in Paris on 22 September 1572.