Despite his modest formal education, Otto Schatzker had an astonishing career as an art dealer and expert in Vienna. He was born illegitimate and given to a foundling hospital. He later grew up with foster parents, who had him baptized. He trained as a cabinetmaker and worked as an errand boy in antiques businesses. Through private study and visits to museums he acquired the necessary knowledge to open his own antiques business in 1915, initially at Lilienbrunngasse 10 in the 2nd district. In 1920 he obtained a business licence for an antiques business at Weihburggasse 6 in the 1st district and at his residence, Köllnerhofgasse 2, also in the 1st district. The company was registered as a sole proprietorship in 1921. In early 1937 Schatzker moved his business to Augustinerstraße 8 in the city centre. Before and above all during the Nazi era, he made purchases on commission for various Austrian and German museums, including the Kunsthistorisches Museum, the Graphische Sammlung Albertina and the Österreichische Galerie in Vienna and the Pinakothek in Munich. He worked as an assessor for the Italian chamber of commerce and had business relations with the Turkish consulate general in Vienna. He employed restorers and photographers and conducted considerable business through the Dorotheum.

After the annexation of Austria, the Vienna office of the Reichskammer der bildenden Künste (Reich Chamber of Fine Arts) banned Schatzker, who was classed as a Jew, from working as an art dealer. In December 1938 the Vermögensverkehrsstelle (Property Transaction Office) appointed Lothar Kitschelt, an art historian and employee of the Kunsthistorisches Museum, as temporary administrator, but he refused the position and had his name deleted from the register of companies in January 1939. In June 1940, the Vermögensverkehrsstelle also revoked the order of December 1939 for the liquidator Otto Faltis to wind down Schatzker's company. In fact, the business in Augustinerstraße had been closed since March 1938. The successor, Josef Neugschwandtner, was conscripted into the Wehrmacht in 1940. It was no longer possible after the war to determine whether the company had been Aryanized and whether Schatzker's stocks were still on the premises. Schatzker had opposed the official liquidation order by transferring at least some of his inventory to his apartment at Köllnerhofgasse 2. The Gestapo also failed to seize the items. Schatzker continued to do business from his apartment – from August 1941 with the permission of the Reichskulturkammer (Reich Chamber of Culture) after the Reichssippenamt (Reich Genealogy Office) had confirmed that he was of "German or related blood". The office stated that as Schatzker's father could not be identified, it accepted Schatzker's undocumented claim that the Jewish mother in the records was not his real mother. Schatzker's name had been registered in the matrices of the Jewish community after his birth; his wife was an "Aryan". In spite of the Reichssippenamt decision, the Gausippenamt in Vienna and the Reichskammer der bildenden Künste (Reich Chamber of Fine Arts) in Berlin continued to investigate Schatzker's origins, with the result that his status during the Nazi era remained uncertain. His relicensing as an art dealer was no doubt due to his international relations and expertise. He also personally gave artworks and other cultural items to Hitler himself and to influential functionaries of the regime. He corresponded with Hans Posse and introduced the Munich art dealer Maria Almas-Dietrich, who in turn did preparatory work for the "Sonderauftrag Linz", to private customers. During the Nazi era, Schatzker travelled abroad – to the Protectorate of Bohemia and Moravia, the Balkans and, on behalf of the Reichsstatthalterei in Vienna, to Florence, where he purchased items for Viennese museums. In 1942 a strong room in the Vienna branch of the Deutsche Reichsbank was made available to him to store art objects.

A Volksgericht trial against Otto Schatzker, his wife Marie and their son Otto Schatzker jun. was opened in summer 1945 for suspicion of illegal enrichment (§ 6 War Criminals Act). They were charged with having acquired artworks and cultural items worth over 2 million Reichsmarks between 1941 and 1945, the foundations of which were laid by purchases from persecuted Jews. Schatzker was also suspected of being a Gestapo informer and of having acquired artworks on behalf of high-ranking Party functionaries. The case was dropped in 1947 and the valuables secured from Schatzker released. Philipphof, where Schatzker's former business had been located at Augustinerstraße 8, was destroyed in an air raid shortly before the end of the war. In 1946 Schatzker had a business with antique jewellery at Köllnerhofgasse 2. The company was deleted from the register of companies in 1960.