Wilhelm Pollak attended the Graphische Lehr- und Versuchsanstalt in Vienna in 1914/15 and worked from 1 March 1927 as a commercial photographer. From 1930 he had a studio at Kriemhild-Platz 13 (from 1934 Kanzler-Platz 13) in Vienna's 15th district and two branches at Vorgartenstraße 41 / Stromstraße 74–76 in the 20th district and Landstraße Hauptstraße 145 in the 3rd district. His sister Margarethe Olga Marjan, née Pollak, and Marianne Pollak had shares in the studio in the 3rd district. Wilhelm Pollak participated in numerous photography exhibitions, including the Photo-Fachausstellung in Vienna in September and October 1930, and published his works in illustrated magazines and newspapers. He was one of the best-known photographers in Vienna in the 1930s, and his studios were among the most successful, arousing hostility and envy among his Nazi colleagues. In 1938 he was living with his wife Stefanie, née Schmid, and daughter at Esterhazygasse 20 in the 6th district. After the annexation, he was persecuted on account of his Jewish origins. Following his refusal to sell his business to his former employee Alfred Wenzel, the photographer Gustav Nohynek, appointed provisional administrator of the three studios, and the guild master and chairman of the "Arisierungskommission" der Fotografenzunft Wien (Aryanization Commission of the Photographers' Guild Vienna) Egon Jelinek looted the businesses and threatened him. Wenzel and Jelinek denounced Pollak and his father Hugo to the Gestapo, and the Landgericht II (provincial court) Vienna ordered them to be put in "protective custody" on 2 May 1938 for alleged utterances hostile to the state, insulting the Führer, "race defilement" and fraudulent bankruptcy. Guild master Jelinek and secretary Franz Brandstätter wrote in a letter of denunciation of 31 May 1938 to the Vermögensverkehrsstelle (Property Transaction Office), stating that Pollak had monopolized most of the photography business in Vienna through extensive public relations and various other types of unserious advertising. Hugo Pollak was murdered in prison on 7 June 1938, and Wilhelm Pollak was released in March 1939 after being forced to sell his studio to his employee Alfred Wenzel. Wenzel Aryanized the studio and its inventory at Kriemhild-Platz 13 in the 15th district. The studio was evaluated by the photographer Robert Thiele on behalf of the Wiener Fotografenzunft (Vienna Photographers' Guild). He drew up extensive inventory lists documenting the studio interior, including numerous pieces of photographic equipment. The photographic plate archive, which Pollak put a high value on in his declaration of assets, consisted of around 70,000 plates. The studio in the 20th district, which had been a competitor to Jelinek, who also had his business there, was liquidated in July 1938 and transformed into local NSDAP offices. The branch in the 3rd district was Aryanized by the photographer Hermann Meroth. Pollak's studio was deleted from the commercial register on 30 August 1938.
Wilhelm Pollak fled to Ottawa, where he acquired Canadian citizenship and died in 1946. Before his death, he wrote a description of his persecution and the Aryanization of his Vienna studios, which was attached to the documentation of Wenzel's prosecution before the Volksgericht in 1947. The studio in the 15th district was bequeathed by Wenzel in April 1945 to Pollak's heirs and restituted in an out-of-court settlement in October 1946. The whereabouts of the photographic plates are unknown.
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).