Son of Charles-Louis du Ry, he studied with Hårleman and J. -F. Blondel before settling in Kassel, where he worked first for Landgrave Wilhelm VIII (1730–60) and then for the enlightened Landgrave Friedrich II (1760–85), creating an urban fabric that survived until its destruction in the 1939–45 war. He further developed the Oberneustadt (Upper New Town) originally designed by his grandfather (completed 1776), and linked it (by means of handsome urban spaces (places) on the French model) to the Altstadt (Old Town) after the fortifications were demolished in 1767. He designed the Museum Fridericianum and observatory (1769–79—the first European purpose-built library/museum of C18), in which French and Anglo-Palladian influences were strong, and a great many other buildings, all of them of quality. In short, he made of Kassel a charming German Court Residence, and so it largely survived until 1945. For Landgrave Wilhelm IX (1785–1821), he designed Schloss Weissenstein (later Wilhelmshöhe), near Kassel (1786–90), the side wings of which were set diagonally, responding to the landscape beyond: it is a great work of Classicism inspired by English and French exemplars, but the over-monumental corps-de-logis (1791–8) was by Jussow. He may have designed some of the fabriques in the park, and was responsible for the Ionic monopteron marking the spring at Bad Hofgeismar, Hessen (1792).
Although much of his work no longer exists, the elegance of du Ry's Neo-Palladianism may be savoured at the charming Schloss Mont-Chéri, Schönberg, near Hofgeismar (1787–9).
Boehlke (1958, 1980);Both & H. Vogel (1973);Dittscheid (1987);Keller (1971);Paetow (1929);Placzek (ed.) (1982);Jane Turner (1996);Watkin & Mellinghoff (1987)