Born in Trebnitz (today Trzebnica), Lower Silesia, Germany (today Poland) into an aristocratic family, she has three brothers and two sisters and is the great-granddaughter of former German Chancellor Georg Graf von Hertling.

Gila von Weitershausen became popular in the late 1960s when she appeared in German comedy films, for example alongside Uschi Glas.

She also appeared several times as "Rowena" in the British TV series Arthur of the Britons.

By common consensus one of her best performances was in Circle of Deceit (1981), a film directed by Volker Schlöndorff, where she played with Hanna Schygulla and Bruno Ganz.

Between 1970 and 1973, she had a relationship with movie director Louis Malle, who is the father of her son, Manuel Cuotemoc (born 1971).