Born in Vienna, the alto began her studies at the University of Music and Performing Arts Vienna, which she completed with distinction, and at the Music and Art Private University of the City of Vienna, where she took a course in classical operetta. Master classes with KS Vesselina Kasarova and KS Robert Holl, among others, enriched her education. Currently the singer is taking lessons with Uta Schwabe. Cornelia Sonnleithner was a finalist in the international competition «Klassikmania» in 2010 and in the Nico Dostal Competition in 2015. From 2012 to 2018 she was a member of the Vienna State Opera Choir and can point to various solos, such as Lehrbub in «Die Meistersinger von Nürnberg», A Fisher Woman in «Peter Grimes», Edelknabe in «Lohengrin». At the Salzburg Festival, she appeared on stage as a farmer girl in «Le nozze di Figaro» and as a madrigalist in «Manon Lescaut». In 2018 the singer sang Hansel in «Hansel and Gretel» in the Ukraine and the Alte Oper Frankfurt in Germany. In February 2019 she made her debut as Barbara Delaqua in «A Night in Venice» at the Vienna Volksoper. In April 2019 the alto singer appeared in Beat Furrer's opera «Desire» at the Teatro Colón in Buenos Aires.