After attending grammar school in Plön he studied German and Romance philology, Danish and history in Freiburg, Kiel and Berlin.
His dissertation was entitled: "The Schleswig-Holstein Newspaper Industry from its Beginnings to 1789".
In 1927 Bülck was admitted to the academic service and passed his subject examination in 1928.
Bülck did research on the Low German language, Schleswig-Holstein literature, especially on Klaus Groth and Friedrich Hebbel, Schleswig-Holstein regional studies, the history of the Christian-Albrechts-Universität Kiel and the history of the Kiel UB.
Literature by and about Rudolf Bülck in the German National Library catalogue