The southern wing was added in the years 1818 - 1825 by another owner of the chateau, Count Ján Keglevič, who at that time held an important position as the main county of Tekov. This classicist wing of the manor is considered to be the most beautiful and purest architectural manifestation of classicism in Slovakia.
For less than two decades, the castle was owned by Archduke Joseph August Habsburg and his wife, Archduchess Augusta, granddaughter of Emperor Francis Joseph I and Empress Sisi.
After the establishment of the First Czechoslovakia, the castle became the summer residence of the presidents of the republic. President TG Masaryk regularly went on two-month stays until 1933. Other presidents also went to the chateau: E, Beneš, J. Tiso, K. Gottwald, A. Zápotocký, A. Novotný.
For its beauty, historical and artistic value, the castle in Topoľčianky in 1970 declared a national cultural monument.
The three Renaissance wings are currently used as a hotel with a restaurant. A museum with historical furniture has been set up in the southern Classicist wing.
The originality and uniqueness of Topoľčianky Chateau also lies in its museum, which houses the most beautiful and rarest pieces of furniture, porcelain and clocks in Slovakia.