Susa was born Charlotta Wegmüller in Gut Gaußen (now part of Kretingalė), East Prussia and first appeared on a stage in 1915 at Tilsit.

Susa gave her debut as a film actress in the German silent movie Der Prinz und die Tänzerin in 1926 and became popular for her roles as a femme fatale.

In 1932 she signed a contract with MGM and moved to the United States to start an international career.

Elizabeth Yeaman wrote in her newspaper column on 15 August 1932: However, Susa did not succeed in Hollywood, returned to Germany soon and canceled the MGM contract in 1934.

Her last role in a movie was a minor one in the 1941 comedy Der Gasmann alongside Heinz Rühmann and Anny Ondra.