Born out of wedlock, Viktor Blahut was a German nationalist from a young age. During the First World War, he served as a non-commissioned officer at the front in Serbia and Italy. From 1921 to 1927, he was a member of the Frontkämpfervereinigung Deutsch-Österreichs, a defence association of the political right in the First Republic. He joined the NSDAP in Vienna in 1927 (membership number 54,293) and was, among other things, co-founder of the Vienna Gau, the first managing director of the regional leadership and active as a district, regional and national speaker. From 1927, he was also a member of the SA, for which he worked as a training director and in the intelligence service, and in 1929, he became the full-time managing director of the Gau Vienna. He maintained close contact with the commander of the Austrian Legion and leader of the SA in Austria, Hermann Reschny. During the period of illegality from 1933 to 1938, Blahut's house was searched numerous times, and he was sentenced to prison and fined several times.
On 12 March 1938, Blahut became an assistant advisor to the social welfare department of the SA Donau group. In June, he applied to the Property Transaction Office (VVSt) for permission to "Aryanise" the Soffer brothers' company, a furniture and antiques business at Singerstraße 4 in Vienna’s 1st district, although he had neither specialist knowledge nor financial means. Supported by the provisional administrator Robert Möder, he obtained preliminary approval in August and – after intervening with the Gauleiter of Vienna Odilo Globocnik, among others – sold the company for a fraction of its actual value and achieved a significant reduction in the "Aryanisation charge" to be paid to the state. In the run-up to the "Aryanisation", he threatened the Jewish owners with the Gestapo and concentration camp incarceration and behaved as a rabid anti-Semite. In 1942, Blahut was promoted to SA-Ehrensturmbannführer.
In 1947, complaints brought by surviving members of the Soffer family, among others, led to several People's Court proceedings against Blahut and Möder. In its judgement of 12 September 1947, the People's Court found Blahut guiltyof high treason in accordance with §§ 10, 11 of the Prohibition Act (VG) because he had belonged to the then banned NSDAP and SA between 1933 and 1938 and had been recognised as an "old fighter" in 1938, had received the NSDAP's Golden Badge of Honour as well as bronze and silver service awards, for abusive enrichment (§ 6 of the War Crimes Act, KVG) in connection with the "Aryanisation" of the Soffer brothers' company and for attempted denunciation (§ 8 StG, § 7 KVG). He was sentenced to five years' imprisonment with forfeiture of assets. Following an appeal by Blahut, the Supreme Court overturned the judgement in 1949 with reference to § 7 KVG; the new sentence was three years' hard labour. Blahut's petition for application of the asset forfeiture amnesty was rejected by the Higher Regional Court in 1957. In the end, there was no expulsion from the country – Blahut's nationality remained unclear until the end. A People's Court case that had been initiated against Blahut's partner Anna Straubinger, partly because she had denounced Moritz Atlas, the owner of a rummage and furniture shop at Ottakringer Straße 28 in Vienna’s 17th district, was quickly dropped.