Born in München, she was the eldest daughter of the writer Thomas Mann and sister of the gay writer Klaus Mann.

Erika Mann had two marriages of convenience, one with the gay actor Gustaf Grundgens (July 24, 1926 to 1929), and one with the British gay poet W.H. Auden (June 15, 1935), this latter in order to obtain a British passport.

Throughout the 1930s she had a personal and professional relationship with Therese Giehse, with wnom she founded "The Pepper Mill", a cabaret. From 1933 she lived first in Switzerland, then in the USA, and then again in Switzerland.