The subject of his highly influential work published in 1985 was the phenomenon of Stasis in classical Greece, which Gehrke posited to be primarily the embodiment of rivalries among the noble classes.
On July 11, 2007, Hans-Joachim Gehrke was elected president of the German Archaeological Institute, succeeding Hermann Parzinger in the position on March 1, 2008.
In the same year, he was appointed honorary professor for the subjects of ancient history and classical philology at the Free University of Berlin.
Gehrke's research focus lies on the history of Greek antiquity, the historical regional study of the central and eastern Mediterranean, the social conflicts and the social integration, the intercultural relationships as well as on ideas about history and collective identities.
Among his academic pupils are Ulrich Gotter, Christian Mann, Peter Franz Mittag, Astrid Möller, Kai Trampedach, Gregor Weber, Michael Sommer, Eckhard Wirbelauer and Felix K. Maier.