This elegant man is Quintijn Simons, a history painter from Brussels. His fashionable cloak draped over his shoulders, half-length hair, dashing moustache and goatee give Simons an air of aristocratic elegance that is characteristic of the portraits of Anthony van Dyck.
Van Dyck lived for many years in Italy, where he became famous for his virtuoso official portraits of prominent members of the nobility. In 1632, he became court painter to King Charles I of England, but he occasionally travelled to the continent to paint commissions like this portrait.