Leys subsequently studied at the Antwerp Academy of Fine Arts: from 1829 to 1832 he studied from the Antique and from 1832 to 1833 he studied drawing from life. During this period he started to work in the studio of his brother-in-law, the genre painter Ferdinand de Braekeleer. One of Leys' teachers at the Academy was Mattheus Ignatius van Bree (1773-1839), the director of the Academy. According to a widely circulated story, during a lecture by van Bree on the draping of the gown and peplos of figures from antiquity Leys made a remark about van Bree's old-fashioned breeches. Van Bree did not appreciate the joke. But as the young hothead refused to apologize, the director expelled him from the Academy. Leys never returned to the Academy, not even as a teacher after he had achieved international success.