He was the brother of Franciscus Sylvius Ambianus (François Dubois; c. 1483 – 1536), professor of humanities at the Collège de Tournai, Paris.

At a young age he studied Ancient Greek with Hermonymus of Sparta[2] and Janus Lascaris,[2] Hebrew with François Vatable,[2] and mathematics with Jacques Lefèvre d'Étaples,[2] and gradually became a leading figure in French humanism, where he was famous for his excellent knowledge of these disciplines.

[3] The title of this work was In linguam gallicam isagωge, una cum eiusdem Grammatica latino-gallica, ex hebræis, græcis et latinis authoribus [Introduction to the French language, with a Latin-French grammar of the same, based on Hebrew, Greek and Latin authors], published in Paris in early 1531, less than a year after the very first French grammar, by John Palsgrave, was published in London.

He studied languages and mathematics at the University of Paris; but feeling that the rewards were inadequate, Dubois abandoned scholarship for medicine.

He acquired his anatomical knowledge thanks to Jean Fagault, a famous physician of Paris and also dean of the Faculty of Medicine.

[5] The success of his lectures turned out to be so remarkable that the faculty of the University of Paris protested that he had not yet obtained a college degree.

In 1550, when Vidus Vidius departed for Italy, he was appointed to succeed him as Professor of Surgery in charge of the new Collège Royal in Paris.

Sylvius was an admirer of Galen, and interpreted the anatomical and physiological writings of that author in preference to giving demonstrations from the subject.

[7] Andreas Vesalius, who was his (frustrated) pupil, states that his manner of teaching was calculated neither to advance the science nor to rectify the mistakes of his predecessors.

Vasse explains the nature of Sylvius' influence over his unruly audience this way: "This depended not so much on his splendid use of the Latin tongue as upon the exceptional clarity of his thought.