She was the fifth of six children born to Anders Gustaf Fahlstedt, a shopkeeper, and his wife Johanna Wilhelmina Bergström.

In order to overcome the financial strain, Fahlstedt taught students and in 1877, she established her own school with the help of her sister Bertha.

She followed this with Ax och Halm (1887), a polemic which explores the themes of marriage, as well as female education and employment.

She also published the short story Ett lefnadsmål which was influenced by the contemporary reform pedagogy ideas.

[1][2][4] Fahlstedt became a close friend of Swedish difference feminist writer Ellen Key.