Sasse studied linguistics, Indo-European, Semitics and Balkanology in Berlin, Thessaloniki and Munich.
In 1975, he received his habilitation with the book Die Morphophonologie des Galab-Verbs and in 1977 he was made a professor.
[2] Sasse was cofounder of the "Documentation of Endangered Languages" (DOBES) initiative of the Volkswagen Foundation.
In 2001, he was elected a full member of the North Rhine Westphalia Academy of Sciences, Humanities, and the Arts.
[4] Sasse was concerned with grammatical relations and lexical categories, language universals, discourse, and grammar, historical linguistics and reconstruction.