The concept of Lebensraum certainly long predated the advent of Hitler and the NSDAP. The geographer Friedrich Ratzel coined the term in 1901 and his various writings in the nineteenth century conceptualized the East as a Kulturlandschaft (cultural landscape) in which German colonization fundamentally altered the East into a verdant landscape. But there were other nationalists and activists beyond Ratzel that popularized the notion that Germany's destiny lay in the East. Gustav Freitag's 1855 novel Soll und Haben, which was a Bildungsroman which valorized the struggle of German colonists of the East over the Slavic and Jewish neighbors, who were often without culture. Soll und Haben was one of the bestselling novels in Imperial Germany and remained popular through the interwar period. There were other societies promoting German colonization and inside Germany itself Ostforschung (Eastern research) scholars collected ethnography, historical data, and other information about the region's allegedly Germanic past.

Perhaps the closest pre-1933 analogue to Hitler's ideas about the East was the activities of Ober Ost during the First World War. As Russian forces retreated from the Western Provinces and the tsarist state was seemingly in a state of collapse, the power vacuum engendered a state of euphoria within the German high command in charge of the Eastern front. The military leaders of Ober Ost created plans for a variety of postwar Germanic states out of the Western regions of the Russian empire, all of which were to be subordinate and coordinated to German power in Berlin. Germany's expansive demands upon the Bolshevik state at Brest-Litovsk was in no small measure an expression of this Ostrausch (Eastern sickness). Even as Germany's apparent victory in 1917 over Russia proved ephemeral and Germany collapsed in 1918, Ober Ost helped funnel military aid to German Freikorps in the Baltics and Poland, some of whom entertained notions of creating a neo-Teutonic military state that would serve as a bulwark against Bolshevism and foster a Germanic Kulturlandschaft. Wartime experience on the Eastern front also popularized notions of Slavic dirtiness and disorder within Germany itself and Ober Ost's visions of Germanic states in Eastern Europe was one picked up by the NSDAP.

Yet it took the NSDAP to take these various preexisting ideas of Lebensraum and transform them into the genocidal and highly exclusionary form often associated with the term. Ostforschung academics in particular "coordinated" quite easily to the new order and their research veered into an exclusionary ethnography that painted all accomplishments of the region as Germanic in origin and denigrated the Slavs' purported "steppe culture" that raped the land. A number of these academics became affiliated with the wartime Generalplan Ost, an SS-led initiative to foster German colonization and transformation of both Poland and the USSR. The NSDAP media also added new exclusionary twists to the genre of the Ostroman genre. In short, the Third Reich took an existing nationalist concept that was already fairly racist and radicalized it.

Yet despite these connective chains, it is dangerous to lend too much continuity between the pre-1933 conceptualizations of Eastern expansion and Lebensraum and its expression in the Third Reich. There are enough significant differences between the two to significantly qualify any attempt to draw a straight line of continuity. For example, although Ober Ost was clearly biased against Slavs in its view of the Eastern future, the military authority's plans for the region's Jews was quite nebulous. Nor did Ober Ost's planners conceive of systematic genocide of the region's non-Germans as a means to achieve its vision of the future. And although Ober Ost enjoyed a degree of power in wartime Germany, it did not have the full support of the central authorities in Berlin, some of whom entertained slightly more realistic plans for the restoration of a client Polish state. In contrast, General Plan Ost's conceptualization of the ethnic makeup of the region was comparatively direct as well as enjoying the full support of the central government. Moreover, many Germans may have read Freitag's novel and others like it as a form of escapism rather than straight-up support for expansionism. Prior to the Weimar Republic, there was little actual systematic support for German colonization or existing German communities in Eastern Europe. In the latter case, such support was often inseparable from postwar politics as the Weimar Republic positioned itself as a protector of minority German rights in Poland and the Baltics for both domestic and international reasons. There were a few efforts to support German colonization of the East, most notably in the eastern regions of the Austro-Hungarian Empire, but these efforts were often relatively small and not mass migration movements. And to add frustration to völkisch precepts behind this colonization, many of the colonists assimilated to local Slavic mores.

This is not to say that Lebensraum and other German conceptualizations of the East prior to the advent of Hitler were benign developments. There usually was a layer of nationalist chauvinism in these concepts and the German discourse on the East often reduced the area to binaries of cultured Germanness and disordered Slavicness. The exclusionary tendencies of such earlier discourses were often latent, but the Third Reich removed any checks on the genocidal potential of these visions and even encouraged them.