Born in Marburg, Jacobshagen studied musicology, history and philosophy at the Free University of Berlin (with Jürgen Maehder), the University of Vienna and Paris as well as culture and media management at the Hochschule für Musik "Hanns Eisler".
He later held a scholarship at the German Historical Institute in Rome and at the Deutsches Studienzentrum in Venice [de].
From 1997 to 2006 he worked as a research assistant at the Forschungsinstitut für Musiktheater of the University of Bayreuth.
Since 2006 he has held a professorship for historical musicology at the Cologne University of Music.
[1] Jacobshagen is a member of the board of the Meyerbeer Institute and the Arbeitsgemeinschaft für rheinische Musikgeschichte [de].