Inspired by the methods of Ernest Labrousse, he attempts to analyze social processes of German society from the perspective of modernisation, industrialization, and the creation of modern Europe.

From 1992 to 1996, Kocka was the founding director and is to date a Senior Fellow of the Centre for Contemporary History in Potsdam.

It gave priority to the study of particular kinds of phenomena, such as classes and movements, urbanization and industrialization, family and education, work and leisure, mobility, inequality, conflicts and revolutions.

In an essay entitled "Hitler Should Not Be Repressed By Stalin and Pol Pot" first published in Die Zeit newspaper on 26 September 1986, Kocka contended against Nolte that the Holocaust was indeed a "singular" event because it had been committed by an advanced Western nation, and argued that Nolte's comparisons of the Holocaust with similar mass killings in Pol Pot's Cambodia, Joseph Stalin's Soviet Union, and Idi Amin's Uganda were "invalid" because of "the backward nature of those societies".

[2] Kocka went on to criticize Nolte's view of the Holocaust as "a not altogether incomprehensible reaction to the prior threat of annihilation, as whose potential or real victims Hitler and the National Socialists allegedly were justified in seeing themselves".