Marr was an unemployed journalist, who claimed that he had lost his job due to Jewish interference. A political conservative, he was influenced by the conservative pan-German movement, as expounded by Johann Gottfried von Herder, who developed the idea of the Volk, and the Burschenschaft movement of the early nineteenth century, which developed out of frustration among German students at the failure of the Congress of Vienna to create a unified state out of all the territories inhabited by the Volk. The latter rejected the participation of Jewish and other non-German minorities as members, "unless they prove that they are anxious to develop within themselves a Christian-German spirit" (a decision of the "Burschenschaft Congress of 1818"). While they were opposed to the participation of Jews in their movement, like Heinrich von Treitschke later, they did allow for the possibility of the Jewish (and other) minorities participating in the German state if they were to abandon all signs of ethnic and religious distinctiveness and assimilate completely into German Volk.
Marr took these philosophies one step further by rejecting the premise of assimilation as a means for Jews to become Germans. In his pamphlet Der Sieg des Judentums über das Germanentum (The Victory of Judaism over Germanism; 1879) he introduced the idea that Germans and Jews were locked in a longstanding conflict, the origins of which he attributed to race--and that the Jews were winning. He argued that Jewish emancipation resulting from German liberalism had allowed the Jews to control German finance and industry. Furthermore, since this conflict was based on the different qualities of the Jewish and German races, it could not be resolved even by the total assimilation of the Jewish population. According to him, the struggle between Jews and Germans would only be resolved by the victory of one and the ultimate death of the other. A Jewish victory, he concluded, would result in finis Germaniae (the end of the German people). To prevent this from happening, in 1879 Marr founded the League of Anti-Semites, the first German organization committed specifically to combatting the threat to Germany posed by the Jews and advocating their forced removal from the country.
Although he had introduced the pseudo-scientific racial component into the debate over Jews in Germany, it is unlikely that he was influenced by the earlier theories of Arthur de Gobineau (author of An Essay on the Inequality of Human Races), who was only translated into German in 1898, a quarter of a century after Marr's pamphlet appeared. Furthermore, Marr himself was very vague about what constituted race and, in turn, the racial differences between Jews and Germans, though this became a feature of Nazi racial science. It remained for later racial thinkers to postulate specific differences: these included Eugen Dühring, who suggested that it was blood, and Houston Stewart Chamberlain, an influential race theorist and husband of Eva Wagner, Richard Wagner's widow, who suggested phrenology as a means of distinguishing races.
On the other hand, it does seem likely that Marr was influenced by Charles Darwin through Ernst Haeckel, a professor who popularized the notion of Social Darwinism among Germany's educated classes.
Despite his influence, Marr's ideas were not immediately adopted by German nationalists. The Pan-German League, founded in 1891, originally allowed for the membership of Jews, provided they were fully assimilated into German culture. It was only in 1912, eight years after Marr's death, that the League declared racism as an underlying principle. Nevertheless, Marr was a major link in the evolving chain of German racism that erupted into genocide during the Nazi era.