After working as a furrier, Timm studied Philosophy and German in Munich and Paris, achieving a PhD in German literature in 1971 with his thesis The Problem of Absurdity in the Works of Albert Camus.

His books Die Entdeckung der Currywurst (The Invention of Curried Sausage) and Am Beispiel meines Bruders (In My Brother's Shadow, or literally: "By My Brother's Example") can both be found in the syllabi of German schools.

His readers usually appreciate Timm's writing style, which he himself calls "die Ästhetik des Alltags" ("the aesthetics of everyday life").

[1] Timm uses everyday vocabulary and simple sentences and generally tries to imitate the way stories are orally told.

Timm's works also tend to have autobiographical features and often deal with, or are set in, the German past.