His father held the office of commissary-general in the military household of Monsieur, afterwards Louis XVIII, but through unforeseen misfortunes young Desnoyers was compelled to choose for himself a career.
He next produced a number of small subjects of similar character, which were well received, and at the Salon of 1799 he exhibited his engraving of Venus disarming Cupid, after Robert Lefèvre, which won a prize of 2000 francs.
From this time he rose rapidly to the first rank in his adopted art, and in 1806 gained the large gold medal for his engraving of the celebrated antique cameo of 'Ptolemy II.
Napoleon in a rage sent in the middle of the night for Baron Denon, and commanded him to go instantly to Desnoyers and ask him to engrave the portrait of the future empress.
The emperor thought it superb, and had already ordered its immediate publication, when he received a faithful miniature of the archduchess, which rendered an alteration of the plate imperative, for the face of the new empress, instead of being round, was a very elongated oval.
Twenty impressions were made when Desnoyers again set to work, and the next day the authentic portrait of Marie Louise was in circulation throughout Paris.
Elected a member of the Institute in 1816, he was appointed engraver to the king in 1825, and created a Baron in 1828, receiving soon after the cross of an officer of the Legion of Honour.