Katia was also a granddaughter of the writer and women's rights activist Hedwig Dohm.

Katia was born in Feldafing near Munich, into one of the wealthiest families in Germany.

At the age of 21, in the fall of 1904, she aborted her studies of physics and mathematics on the request of her mother and aunt, to marry the writer Thomas Mann on 11 February 1905, in Munich[clarification needed].

In addition, she typed for her husband and arranged his appointments on top of the tasks of a large household.

[2] Hedwig realised that her daughter needed rest, and in January 1912, Katia was one of the first patients to be admitted to the Wald Sanatorium in Davos, Switzerland.