Afterwards, from 1999 to 2005, he was assistant professor at the Kunstgeschichtliches Institut of the Goethe University Frankfurt, where he did his habilitation in 2005 with a research thesis on the pictorial reform of the Early modern painter’s family of the Carracci from Bologna.

Directly afterwards Keazor became guest professor at the Johannes Gutenberg University of Mainz before he then, from 2006 on, got the Heisenberg-fellowship of the German Research Foundation (Deutsche Forschungsgemeinschaft: DFG).

In September 2012, Keazor changed to the Institut für Europäische Kunstgeschichte of the Heidelberg University where he assumed the succession of Raphael Rosenberg, whose post, the professorship of early modern and contemporary art history, had been vacant since 2009.

With the collection, named after the god for fire and crafts Hephaistos (Latin Hephaestus), art forgeries provided by the State Criminal Police Offices Berlin, München and Stuttgart from their evidence rooms are available for teaching.

The goal is not only to sensitize students to forgeries they may encounter later in their careers, but also to use these objects, which (unlike works kept in museums) allow direct examination, to convey much of what is also relevant to art sold as originals (style, painting technique, provenance, etc.).