After graduating from the Hindenburg School (now Humboldt-Gymnasium Düsseldorf) in 1927, he became a member of KPD which he left after five years, following a trip to Moscow (his mother's native city) in 1931, and having begun to detest the ideological narrowness of the movement.
Flechtheim studied law and political science at the universities in Freiburg, Paris, Heidelberg, Berlin, and finally Cologne.
In 1946 he returned to service in a rank of lieutenant colonel, joining for several months the Office of the US Chief of Counsel for War Crimes in Germany.
After the integration of that institution into the Free University of Berlin in 1959, he became a professor of political science at the local Otto-Suhr-Institut, the position he held until his retirement in 1974.
[1] Flechtheim died on the eve of his 89th birthday in his adopted hometown of Berlin, and was buried in Dahlem Cemetery plot 2, next to some of his political friends interred there.
The founding father of modern futurism, if there is one, may well be a mild-mannered German professor who, as early as the mid-1940s, began speaking and writing about the need for what he termed "futurology."...
I held that, by marshaling the ever growing resources of science and scholarship, we could do more than employ retrospective analysis and hypothetical predictions; we could try to establish the degree of credibility and probability of forecasts."
Flechtheim's concept of futurology around that time was based on the process of social evolution that was emerging in Eastern and Western Europe, leading a "Third Road" beyond capitalist and communist systems and would mean a new democratic alternative to existing societies.