She cited reading Amtmandens Døtre (The Official's Daughters, 1855) by Camilla Collett and Henrik Ibsen's plays Kjærlighedens komedie (Love's Comedy, 1862), Brand (1865), and Peer Gynt (1867) as her childhood influences.

[4] After a correspondence with Urban von Feilitzen [sv], who wrote Protestantismens Maria-kult (The Protestant Cult of Mary, 1874), she had written a review of the book for a periodical, under the pseudonym Robinson.

[3] In 1885, she was one of the five founding members of the women's society Nya Idun, along with Calla Curman, Hanna Winge, Ellen Fries, and Amelie Wikström.

[7] Even though Key did share a lot of similar beliefs with the members of the Fredrika Bremer Association, two main issues made her oppose the group in the mid-1880s: the importance of sexuality and the social significance of the biological differences between women and men.

1886 saw Key publishing Om reaktionen mot kvinnofrågan (On the Reaction against the Woman Question) which was highly critical and argued against the egalitarian tendencies of the Swedish women's movement.

The piece was published in Gustaf af Geijerstam's journal Revy i litterära och sociala frågor (Review of Literary and Social Issues).

[3] Also in 1886, she wrote a review of En sommarsaga (A Summer Story, 1886) by Anne Charlotte Leffler in the short-lived journal Framåt [sv] (Forward).

Key contributed to three journals all with different views on women's rights: Tidskrift för Hemmet, Dagny, and Framåt.

The latter was edited by Alma Åkermark from Gothenburg and tended to have taboo information, including publishing texts on syphilis, sexual repression and socialism.

Mathilda Malling's Pyrrhus-segrar (Pyrrhic Victories), published in 1886 under the pseudonym Stella Kleve, was very controversial among Scandinavian intellectuals.

[3] Also in Naturenliga arbetsområden för kvinnan (Natural Lines of Work for Women) and Kvinnopsykologi och kvinnlig logik (Female Psychology and Logic, 1896) Key said a "monogamous heterosexual relationship aimed toward procreation formed the crux of a woman's happiness and fulfillment.

She is quoted as having said: In the late 1880s–early 1890s, Key decided to write biographies of women who had prominent roles in Swedish intellectual life; they were: Victoria Benedictsson, Anne Charlotte Leffler, and Sonia Kovalevsky.

[citation needed] These works include: On education, her earliest article may be Teachers for Infants at Home and in School in Tidskrift för hemmet (1876).

[11] Several of Key's writings were translated into English by Mamah Borthwick, during the period of her affair with Frank Lloyd Wright.

[12] Among her best-known works published in English: She has inspired writers such as Selma Lagerlöf, Marika Stjernstedt, Waka Yamada and Elin Wägner.