The following year he received his doctorate in Frankfurt with a dissertation on "France in the politics of the Prussian statesman Wilhelm von Humboldt".
From 1972 he was professor for general historical methodology and History of Historiography [de] at the University of Frankfurt am Main.
[2] Muhlack has intensively studied the theory of history and the historiography of humanism (especially the example of Beatus Rhenanus).
Die Vorgeschichte des Historismus is considered his most important monographic publication.
At present he is working on an edition of the correspondence between the Bavarian Academy of Sciences and Leopold von Ranke.