Sermisy was most likely born either in Picardy, Burgundy, or Île-de-France, based on the similarity of his surname to place names there. Sometime in his early life he may have studied with Josquin des Prez, if Pierre Ronsard is to be believed, but many musicologists consider the claim unreliable; at any rate he absorbed some of the older composer's musical ideas either early, or later, as he became acquainted with his music. Josquin was possibly at the French court between 1501 and about 1503, though this has never been definitely established, so a master-pupil relationship would have been possible then; Sermisy's whereabouts before 1508 are not known, but presence at the Royal Chapel was certainly possible.