Lil Dagover was born Marie Antonia Siegelinde Martha Seubert in Madiun, Java, Dutch East Indies (now Indonesia) to German parents.

[5] Her father, Adolf Karl Ludwig Moritz Seubert, born in Karlsruhe/Baden Germany, was a forest ranger in the service of the Dutch colonial authorities.

[citation needed] Seubert began using a variant of her husband's surname as a professional moniker – changing the spelling of "Daghofer" to "Dagover".

The same year, she was directed by Robert Wiene in the German Expressionist horror classic Das Kabinett des Doktor Caligari, from a script by Carl Mayer and Hans Janowitz opposite actors Werner Krauss and Conrad Veidt.

By the early 1920s, Dagover was one of the most popular and recognized film actresses in the Weimar Republic, appearing in motion pictures by such prominent directors as F. W. Murnau, Lothar Mendes and Carl Froelich.

[citation needed] After her return to Germany and the rise of the Third Reich in 1933, she avoided overt political involvement and generally appeared in popular costume musicals and comedies during World War II.

[12] In 1960, Dagover began appearing in numerous West German television roles in addition to continuing to perform in film.

Dagover's last film role was at age 91 in the 1979 Maximilian Schell-directed and produced drama motion picture Tales from the Vienna Woods.