Born in Schwedt, Gilly was the son of a French-born Huguenot immigrant named Jacques Gilly and his wife Marie Villemain. His brother was the physician Charles Gilly. Already at the age of fifteen, Gilly was working in the gardens on the Netze. Becoming a specialist in building water-features, he was appointed master builder in 1770, and was active between the years 1772 and 1782 in Stargard, Farther Pomerania. Gilly was the first examinee of the newly established Ober-Examinationskommission. Around 1777, Gilly married Friederike, a daughter of the regimental stable-master Friedrich Ziegenspeck. With her he had two children, Friedrich and Minna. In Stargard, Gilly was in 1779 promoted to building director of Pomerania, before being transferred in 1782 to Stettin. As a building director, he designed responsibly for the harbour company of Swinemünde and Kolberg. Because Gilly had already made himself widely known among the new generation of newly-qualified architects, he established the "Cameralbau" in Stettin. For King Frederick the Great, he acted as a source of expertise for comprehensive land improvement schemes. In 1788 Gilly was recalled to Berlin, into the Oberbaudepartement. There he was promoted that very year to be architectural advisor for the provinces of Pomerania, East Prussia and West Prussia, responsible for Kurmark and Altmark. His appointment as vice director of the construction and inspection department lasted four years. As such, Gilly was from 1792 to 1801 in charge of the building of the Bromberger Canal and the reconstruction and extension of the harbour concern of Danzig and Elbing. Gilly later founded a private architectural school in Berlin in 1793 and five years later was one of the co-founders of the Berliner Bauakademie. In these years, Gilly created some of his most beautiful works: in 1796 the country seat at Paretz in Potsdam for King Frederick William III, and two years later the SchlossFreienwalde for Queen Louise. Gilly conceived and erected a city palace in Braunschweigand for the publisher Eduard Vieweg in 1801 and almost at the same time he rebuilt Schloss Steinhöfel for the HofmarschallValentin von Massow. When on 3 August 1800 his son Friedrich died, he lost his creative impulse, even finding no pleasure in a short study trip to Paris in 1803/04. His wife Friederike died in 1804 and after the obligatory year of mourning, Gilly married her sister, Juliane Ziegenspeck. At the age of 60, on 5 May 1808, Gilly died in Berlin. His grave in Berlin in the ProtestantFriedhof II der Jerusalems- und Neuen Kirchengemeinde was rediscovered and renovated in 1938.
Writings
Beschreibung der Feuer abhaltenden Lehmschindeldächer : nebst gesammelten Nachrichten und Erfahrungen über die Bauart mit getrockneten Lehmziegeln.
Grundriß zu den Vorlesungen über das Praktische bey verschiedenen Gegenständen der Wasserbaukunst.
Vergleichung der verschiedenen Bauarten welche bey Gründung der im Meere erbauten Werke, vorzüglich aber bey Aufführung der Hafen-Wände oder der sogenannten Molen an den See-Häfen, gebräuchlich sind.
Sammlung nützlicher Aufsätze und Nachrichten.
Ueber Erfindung, Construction und Vortheile der Bohlen-Dächer.
Handbuch der Landbaukunst.
Kurze Anleitung auf welche Art Blitzableiter an den Gebäuden anzubringen sind.
Abriss der Cameral-Bauwissenschaft.
Praktische Anleitung zur Anwendung des Nivellirens oder Wasserwägens in den bey der Landeskultur vorkommenden gewöhnlichsten Fällen.
Praktische Anweisung zur Wasserbaukunst.
Über die Gründung der Gebäude auf ausgemauerte Brunnen.
Sammlung von Aufsätzen und Nachrichten die Baukunst betreffend
Buildings
Schloss Steinhöfel
Gutshaus :de:Bäke #Hake’scher Gutshof mit Burg und Schloss|Kleinmachnow 1796-1803