Gustav Nohynek is thought to have started his career as a photographer in the early 1930s. He joined the NSDAP on 14 October 1931, Neubau district (membership number 611971), and from 1932 was a member of the Sudetendeutsche Landsmannschaft Elbetal, also in the Neubau district of Vienna, and was a member of the SA. During the Austrofascist era he began to work as a photographer after being appointed in May 1934 to the advisory board of the newly created Gehilfenausschuss der Fotografen (organization of young trainee photographers). Until December 1935 he was a member of the Verein fotografischer Mitarbeiter (association of photography employees) and then became proprietor of an enlargement and retouching studio, Graphische Kunstanstalt Gustav Nohynek, at Schottenfeldgasse 24/9 in the 7th district. Until 1938 he was responsible in the NSDAP for the purchase and sale of various illegal magazines (Kampfruf, Österreichischer Beobachter) and Winterhilfsmarken (winter relief stamps) and was also active in the "Antisemitenbund" (Antisemite League). After the annexation he worked without pay in the Deutsche Arbeitsfront (DAF) (German Labour Front) and was Blockwart (warden) in the Alsergrund district of Vienna. In 1938 he rose in the Nazi organization structure within the photographers' guild. He soon became a member of the elite circle of guild functionaries who organized and profited from the Aryanization and liquidation of Jewish photography businesses. In March 1938 he was already deputy to the recently appointed temporary guild master Egon Jelinek, and as a member of the Aryanization Commission played a key role in the Aryanization of the photography sector. From August 1938 he was appointed by the Staatskommissar in der Privatwirtschaft (State Commissar for Private Industry) as temporary administrator of the businesses of Eugen Grünberg, Nachim Chefez, Wilhelm Pollak and Oskar Weitzmann. He also profited from the Aryanization of Anna Weitzmann's studio (S. Weitzmann), which he managed from November 1938 initially with Johann Poppovic and then from 1941 on his own. He was also a member of the advisory board of the Wiener Fotografenzunft (Vienna Photographers' Guild) and a functionary (Kreisfachschaftswalter) in DAF district I. In 1940 he succeeded Jelinek as master of the Vienna guild and was appointed by the Reichsinnungsverband (Reich Association of Guilds) as deputy Bezirksinnungsmeister (district guild master) for the Ostmark.

After the war, the Volksgericht brought two charges against him at the Landesgericht für Strafsachen Wien (provincial court for criminal matters) in Vienna. In July 1946 he was charged under § 11 des Verbotsgesetz (Prohibition Act) (high treason) and § 6 and § 7 of the Kriegsverbrechergesetz (KVG) (War Criminals Act) (illegal enrichment and denunciation) in connection with the Aryanization of Atelier S. Weitzmann. He was convicted and sentenced to two years' imprisonment. He was acquitted in 1950 of a second charge in 1947 under § 7 KVG of participation in damage through denunciation in connection with the Aryanization of Wilhelm Pollak's studio. After his release from prison, he worked again as a photographer and owner of Fotokeramik Gustav Nohynek at Obere Amtshausstraße 21 in the 5th district. He died in Vienna in 1961.

From the project Durch das NS-Regime aus Österreich vertriebene und ermordete Fotografinnen und Fotografen und der Verbleib ihrer fotografischen Sammlungen (Subsidized by the National Fund of the Republic of Austria. Conducted by Walter Mentzel).