Klösz undertook an apprenticeship as a pharmacist. He subsequently worked in Vienna, and in Budapest. He was known for his photographs of the city of Budapest. He was part of the Viennese Photographers’ Association that had exclusive photographic rights to document the Vienna world’s fair of 1873.

Fellner-Feldhaus, M. (2004). "Fotografischer Schauplatz Weltausstellung. Dokumentation und Inszenierung." In Technisches Museum Wien (ed.), Welt ausstellen. Schauplatz Wien 1873, Wien: Technisches Museum Wien, p. 11–34.

Niemand, F. (2019). Orientalische Architektur und fotografische Dokumentation der Wiener Weltausstellung 1873, Masterthesis, University of Vienna 2019.