The young Austrian mezzo-soprano Anja Mittermüller began her musical education at with Thomas Künne and is currently studying at the Hanover University of Music, Drama and Media with Marek Rzepka.
Alongside her studies, the mezzo-soprano has participated in masterclasses with Brigitte Fassbaener, Margit Fussi, Claudia Visca, Kurt Equiluz, Robert Holl, Sir András Schiff and Franz Welser-Möst, among others. Together with her duo-partner and pianist Richard Fu, she was awarded first prize in the Wigmore Hall/Bollinger International Song Competition in 2024, making her the youngest winner in the competition's history.

In recent years, she has made her debuts at the Klosterneuburg Opera in Verdi's La forza del destino (Curra) under the direction of Christoph Campestrini, and at the Vienna Konzerthaus in recital as part of Musica Juventutis, followed by a recital at the Konzerthaus Blaibach. Anja Mittermüller performed with Robert Holl at the Schubertiades in Dürnstein and Atzenbrugg and appeared alongside Michael Schade and Justus Zeyen at the Randhartinger Serenade. She could also be heard together with Daniela Fally and Adrian Eröd at the festival Klassik.Klang Berndorf. In December 2024, she performed Mozart's Requiem with the Tonküstlerorchester Niederösterreich under the direction of Andreas Ottensamer and made her debut at the Wiener Musikverein as a soloist in Schumann's Der Rose Pilgerfahrt with the Wiener Singverein and under the direction of Johannes Prinz. In August 2025, Anja Mittermüller made her debut at the Bregenz Festival as Tisbe in Rossini's La Cenerentola.
The 2025-2026 season, includes a Christmas Concert at the Salzkammergut Festwochen in Gmunden (recorded for the Austrian Television), Bach's Magnificat for the first time with the Tonkünstlerorchester Niederösterreich under Stefan Gottfried, and Bruckner's Te Deum under Yutaka Sado, as well as Haydn's Paukenmesse with the Vienna Chamber Orchestra under the baton of Jan Willem de Vriend at the Vienna Konzerthaus. Lied recitals brought her to the Heidelberger Frühling, the Eppaner Liedsommer, the :alpenarte Schwarzenberg and London's Wigmore Hall. A further highlight were Schubertiades with Sir András Schiff and Julian Prégardien at the Vienna Konzerthaus and the Kronberg Academy.
During the summer of 2026 Anja Mittermüller will make her debut at the Salzburg Festival. She takes part at the Young Singer’s Project and will sing the role Dryade in a new production of Richard Strauss’ Ariadne auf Naxos alongside Elina Garanca and under the baton of Manfred Honeck.