Schelsky was born in Chemnitz, Saxony. He turned to social philosophy and even more to sociology, as elaborated at the University of Leipzig by Hans Freyer (the "Leipzig School"). Having earned his doctorate in 1935 (thesis [tr.]: The theory of community in the 1796 natural law by Fichte), in 1939 he qualified as a lecturer ("Habilitation") with a thesis on the political thought of Thomas Hobbes at the University of Königsberg. He was called up in 1941, so did not take up his first chair of Sociology at the (then German) University of Strasbourg in 1944.

After the fall of the Third Reich in 1945, Schelsky joined the German Red Cross and formed its effective Suchdienst (service to trace down missing persons). In 1949 he became a Professor at the Hamburg "Hochschule für Arbeit und Politik", in 1953 at Hamburg University, and in 1960 he went to the University of Münster. There he headed what was then the biggest West German centre for social research, in Dortmund.

In 1970, Schelsky was called to be the first rector of the newly founded Bielefeld University (creating by the way the only German full "Faculty of Sociology", and the "Centre of Interdisciplinarian Research" ("Zentrum für Interdisziplinäre Forschung" [ZiF] at Rheda), planned to be a 'German Harvard'). However, his new university changed very much, due to the years of student unrest all over Europe and North America, so he returned to Münster in anger, in 1973, for another five years. Having been a busy and successful publisher and editor all his life, he wrote several more books, against the Utopian way to approach Sociology, as fostered by the Frankfurt School, and on the Sociology of Law, but died a broken man in 1984.

The "Leipzig School" (the social philosopher Hans Freyer, the anthropologist Arnold Gehlen, the philosopher Gotthard Günther), rich in the talents of a first generation, was of strong theoretical influence on Schelsky. But Freyer also dreamt of building up a sociological think tank for the Third Reich - quite differently to most other sociologists, e.g. to the (outspoken) anti Hitlerian Ferdinand Tönnies (University of Kiel) and to Leopold von Wiese (University of Cologne), and to the émigrés (e.g. to Karl Mannheim, and to the up - and - coming René König, Paul Lazarsfeld, Norbert Elias, Theodor Adorno, Rudolf Heberle, and Lewis A. Coser). Freyer's ambitions failed miserably, the Nazi power elite monopolizing ideology, but helped the talented (and former Nazi) student Schelsky in his first career steps.

After the Second World War, no longer a National Socialist, Schelsky became a star of applied sociology, due to his great gift of anticipating social and sociological developments. He published books on the theory of institutions, on social stratification, on the sociology of family, on the sociology of sexuality, on the sociology of youth, on Industrial Sociology, on the sociology of education, and on the sociology of the university system. In Dortmund, he made the Social Research Centre a West German focus of empirical and theoretical studies, being especially gifted in finding and attracting first class social scientists, e.g. Dieter Claessens, Niklas Luhmann, and many more.

It helped that Schelsky was an outspoken liberal professor, without any ambition to create adherents - a rare bird among German mandarins. He helped another 17 sociologists qualify as lecturers (outnumbering in this any other professor in the Humanities and Social Sciences) and anticipated the boom in sociological chairs at German universities. Manning them, he was professionally even more successful than the outstanding remigrants René König (Cologne) and Otto Stammer (Berlin) - the Frankfurt School starting to be of influence only after 1968.

Schelsky was able to design Bielefeld University as an innovative institution of the highest academic quality, both in research and in thought. But the fact that his own university had moved away from his ideas hit him hard. His later books, criticizing ideological sociology (very much acclaimed now by conservative analysts) and on the sociology of law (quite influential in the Schools of Law) kept up his reputation as an outstanding thinker, but fell out of grace with younger sociologists. Moreover, his fascinating analyses, being of highest practical value, went out of date for the same reason; only by 2000 did new sociologists start to read him again.