 In 1867 Stiassny was appointed delegate to the Paris Exposition by the Ministry of Commerce, and the following year he settled in Vienna as an architect.Until 1905 he oversaw the construction of 180 palaces, schools, residences, factories, hospitals, and synagogues, including the Rothschild Hospital at Währing (1873), the Hall of Ceremonies in the Jewish section of the Vienna Central Friedhof, the Königswarter Institute for the Blind at Hohewarte, the Kindergarten in the second district of Vienna, the Rothschild Hospital at Smyrna, and the synagogues at Malacky, Jablonec nad Nisou, Čáslav, and Weinberge (Vinohrady, now a part of Prague).From 1878 to 1900 Stiassny was a member of the aldermanic board of Vienna and of the Donauregulierungs-Commission.