Theresa Dlouhy studied siwith Lydia Vierlinger at the University of Music and Performing Arts in Vienna. She worked with ensembles as the Bach Consort Vienna, Franui, the L'Orfeo Baroque Orchestra, Rayuela, the Ensemble Platypus the Vienna Academy shape and under the batton of conductors as Walter Kobéra, Johannes Kalitzke, Peter Rundel, René Clemencic, Manfredo Kraemer and Friedrich Cerha.

She worked with the Austrian ensemble Mikado (CD appearances on the label Gramola), mainly concerned with the music of the English Renaissance. In 2008 she founded together with gambist Eva Reiter in 2008 the ensemble UNIDAS, which in 2009 expanded into a trio with the lutenist Christopher Dickie(CD "Alas poore Men" on the label Gramola).

Another focus for Theresa Dlouhy is opera. Recently she figured as Flaminia (Haydn) as Teofane (Handel) Galatea (Handel), Euridice (Gluck), as Königstochter in Wolfgang Mitterer's „Das tapfere Schneiderlein“, as Serpetta (Mozart) as Princess in Ali Askins „Eisenhans !“, as Elisetta (Cimarosa), as Valencienne (Léhar), in „Anæsthesia“ together with Franui and Nico and the Navigators at the Händelfestspiele Halle, at the Bregenzer Festspiele, in the Radialsystem Berlin, in the Grand Theater Luxembourg and Enschede, as Kammerzofe in the premiere of the opera „Die Gänsemagd“ (Iris ter Shiphorst), as Axia in „PlayZero“ (Wolfgang Mitterer), in the title role of the children's opera „Das kleine Gespenst“ by Walter Soyka (premiere in 2011 at the Graz Opera), as Prinzessin vom Mond in Wolfgang Mitterer's comic opera „Baron Münchhausen“ (at Musica Strasbourg and Kampnagel Hamburg) and in three short operas of the production "Gates / Gäste!" (Karusell - Mirela Ivicevic, Axi - Jaime Wolfson, Inventory - Fernando Riederer) during the World Music Days, in the world premiere of the sitcom opera Bernhard Gander's „Das leben am Rande der Milchstraße“ at the Bregenzer Festspiele and at Wien Modern and as Emma in the children's opera "Schneewittchen" by Wolfgang Mitterer.