From 1898, Bäumer lived and worked together with the German feminist and politician Helene Lange.

Bäumer edited the Handbuch der Frauenbewegung [Handbook of the Women's Movement] from 1901–1906.

As such, Bäumer was aggressively opposed to the feminist-pacifist women supporting internationalism in Germany and elsewhere; stating: "We mustn't ever forget that it is not just military training that is being put to the test out there in the trenches and at sea, at the gun emplacements and in the air, but also German mothers' upbringing and German wives' care.

"[3] After the war she joined the German Democratic Party, for which she was a Reichstag member between 1919 and 1932.

[2]: 93 Gertrud Bäumer's published works as cited by An Encyclopedia of Continental Women Writers.