According to the sources he began his studies with the Swiss painter Benedikt Klaus, who was active in both Vienna and in Royal Hungary.
According to his contemporary biographer, the Swiss Johann Caspar Füssli, the Protestant Kupecký, who faithfully clung to his ancestor's religion, remained withdrawn and isolated in Vienna's Catholic milieu, which was under the influence of the court and the aristocracy.
He painted portraits of various members of the dynasty, Prince Eugene of Savoy, several aristocrats, and, in Karlovy Vary, even of the Russian Czar Peter I.
The rich oeuvre of this period comprises a series of gorgeous portraits of Kupecky's family, friends and the painter himself, as well as several persons, whose identity in unknown.
As the most significant portrait painter of contemporary Germany, he was commissioned by many German princes, church dignitaries rich merchants and scholars, and his works were popularized by engravings even during his lifetime.