[3] In 1916, Stemmler began teaching at a primary school in Berlin-Moabit and simultaneously worked in the archive of the Association of German Mechanical Engineering Institutions.

Joining the communist party in 1932, she began co-editing the journal Roter Westen (Red West),[3] but was arrested after Hitler's rise to power in 1933.

After a short confinement in prison, she emigrated to Prague, Czechoslovakia, where she began working at the Arbeiterverlag (Workers' Publishing House),[2] editing anti-fascist material.

[1][5] She began working as a nurse in the International Brigades of the Spanish Civil War at the medical center set up in Murcia.

[3] Stemmler began working at the Eberswalde Upper District Office in the Soviet occupation zone in August 1945.

In 1950, Stemmler began working at the Municipal Communication Archive in Schwielowsee[2] and at the end of that year was asked by the Socialist Unity Party of Germany (German: Sozialistische Einheitspartei Deutschlands, SED) to take over the chair of the Zauch-Belzig District Council [de].

[3] Stemmler was honored with the Clara Zetkin Medal in 1966 and the following year received the silver Patriotic Order of Merit from East Germany.

[3] In 1967, at a ceremony held at the Zwinger Palace in Dresden, she was honored with the Florence Nightingale Medal for her service as a volunteer military nurse.

[3] In the 1970s, a combined nursery and kindergarten in Potsdam-West was named in her honor, recognizing her efforts in anti-fascist activities directed at youth.