[2][4] She briefly worked at a children's home near Cottbus, before taking a job as a publishing clerk for Schönheit magazine, where she primarily wrote book reviews.

In January 1920, the project, called Volkshochschule Hannover (Adult Education Center of Hanover) opened, and Ada took the role of chief administrator.

In this role, Lessing managed and organized the center's instructional program, bringing in volunteer teachers and implementing a decentralized classroom system.

[4] Lessing became a parliament candidate of the Social Democratic Party of Germany in the March 1933 German federal election, in the midst of the Nazi seizure of power.

Her husband Theodor, who faced persecution for being Jewish and Socialist and had had his teaching license revoked, had fled to Marienbad, Czechoslovakia, where he was murdered in August 1933.

[4] From July 16, 1951, to November 9, 1952, Lessing was a representative for the Social Democratic Party of Germany in the Hameln-Pyrmont district council, and was active in its welfare and health committee.