By 1965 Fischer studied biology, then the Germanic, Protestant theology and rhetoric in general, the Universities of Basel and Zurich. In 1965 he passed his First State Examination in the subjects German and Protestant theology and a doctorate in 1967 in the Rhetoric with a thesis on Kindle speech. Poetry and rhetoric in the literary theory of the Baroque period in Germany. (Tübingen, 1968). He then worked as a lecturer for German language and literature at Stockholm University and Research Associate at the Institute of German Philology, General and Comparative Literature at the University of Berlin.
In 1976 the habilitation of German Philology at the University of Berlin and since 1978 he has been Professor of Modern German Literature at the University of Hamburg. Since 2004 he has been retired.