Alexander Fleischer was awarded prizes at international competitions early on, including the Lied accompanist prize at "Das Lied" International Song Competition Berlin 2009. He has performed at the Lucerne Festival, Musikverein Vienna, Festspielhaus Baden-Baden, Philharmonie Cologne, Music Festival "Heidelberger Frühling," Konzerthaus Berlin, festspillene i bergen, Festival RheinVokal, and the Hugo-Wolf-Akademie Stuttgart, among others.
He works with singers such as Bo Skovhus, Roman Trekel, Thomas Quasthoff, Manuel Walser, Tobias Berndt, Nikola Hillebrand, Jochen Kupfer, Andreas Wolf, Daniela Sindram, and others.
Alexander Fleischer holds a guest lectureship at the Hanns Eisler School of Music Berlin and has been working as assistant to KS Prof. Thomas Quasthoff since 2011.
In April 2015 he became a teaching position for Lied interpretation at the Würzburg University of Music. In 2017 he was a lecturer at the renowned Britten Pears Festival in Aldeburgh (UK).
In 2017 he founded his own song festival. The "Hirschberger Liedfest" takes place for the 5th time in 2021.
His highly-praised CD with Goethe settings by Fanny Hensel with baritone Tobias Berndt was released on the querstand label. In 2020 the CD "Legacy" with Catalan-Spanish repertoire was released together with mezzo-soprano Anna Alàs i Jové on SEED MUSIC.