Like her brother Otto, Clotilde, the eldest daughter of the drive belt manufacturer Moriz Brill and his wife Amalie, was born in Pardubice, Bohemia. Shortly afterwards, the family moved to Vienna, where sisters Wilhelmine (1884) and Elfriede (1893) were born. Clotilde devoted herself to studying English and French and then worked as a translator. Her marriage to Ludwig Schweiger, assistant at the Neurological Institute of the University of Vienna, on 4 July 1905, resulted in daughter Hertha Marie, who was born in 1907. In the same year, the couple commissioned Adolf Loos to decorate their shared apartment at Alserstraße 22, in Vienna’s 9th district, which could be viewed as part of the so-called apartment tours on 11 December 1907. Ludwig Schweiger died unexpectedly on 25 November 1909. On 20 December 1917, Clotilde married the regimental doctor Károly Grosz in the garrison synagogue in the Rossau barracks. The marriage was divorced on 24 October 1922, and Clotilde took her first husband's surname again. From the 1930s onwards, Clotilde Schweiger became increasingly active as a translator and wrote numerous book reviews, which were published in the Neue Freie Presse, among others. From 1933, together with her daughter Hertha, who had completed a doctorate in musicology at the University of Freiburg im Breisgau, she ran a literary salon in her apartment in Vienna's 19th district, where she regularly received artists and writers such as Eric Voegelin, Hermann Broch, Emanuel Winternitz, Sir Felix Maximilian Cassel and Elizabeth de Waal.

After the annexation of Austria to the German Reich in March 1938, Clotilde Schweiger was persecuted due to her Jewish origins. Clotilde Schweiger finally countered the increasing exclusion from all areas of life and the associated progressive deterioration of her living situation by fleeing. On 1 July 1938, she applied for an export permit for her “removal goods”, which included paintings, carpets and knick-knacks. Clotilde complied with the Regulation on the Declaration of Assets of Jews on 15 July 1938. The “Industrial Palace” at Franz-Josefs-Kai 7–9, jointly owned by the Brill siblings, was forcibly sold to the Reich Treasury in September/October 1938 and subsequently used by various branches of the Wehrmacht. Clotilde Schweiger left Vienna at the beginning of August 1938, reaching New York via Zurich, Tourettes in the south of France and Genoa in February 1940, where she became a US citizen. Her daughter Hertha had already fled to the USA via Switzerland and Great Britain in the summer of 1938. Clotilde Schweiger never returned to Austria and died on 28 January 1947 in Piermont, New York. The “Industrial Palace” was not restituted until 1955.