In 1985, she became a research assistant to Ilja Mieck at the Friedrich Meinecke Institute of Freie Universität Berlin.
In 1987, she received her doctorate from the FU Berlin with the thesis Josephinian Reforms and Social Change in Transylvania.
Schaser's main areas of research and teaching include religion and society in the 19th century, the German Empire and the Weimar Republic, the history of historiography, self-testimonies of the early modern and modern periods as sources of historical scholarship, and the history of the women's movement in Germany (1865-1933).
[3] From 2004 to 2010, Schaser was a member of the DFG research group "Selbstzeugnisse in transkultureller Perspektive" (Self-testimonies in transcultural perspective) based at the FU Berlin; she organised numerous workshops and conferences and published essays.
Schaser had justified the cancellation of a paid teaching assignment in writing with the fact that the person concerned had shortly before made critical comments on WDR about the situation of lecturers.