Anna Whitlock was the daughter of the merchant Gustaf Whitlock and Sophie Forsgrén, and the sister of the feminist Ellen Whitlock. When her father, a moderately well off businessman, was ruined, the family was supported by her mother, who was many years younger than her father, and who educated herself as a photographer and worked as a translator to support the family. It is said that Anna Whitlock was given her interest in women's issues from her mother: after an inheritance, Sophie Whitlock engaged in building, and had apartment buildings set up for female professionals, and she also worked as a secretary for the women's organisation Fredrika Bremer Association.
Anna Whitlock studied at the Rossander Course. She worked as a teacher at the Adolf Fredriks folkskola in Stockholm in 1869–70 and as a governess in Finland in 1870–72 before enlisting as a student at the Högre lärarinneseminariet in Stockholm, from which she graduated in 1875. Between 1876 and 1878, she studied language and pedagogy in Switzerland, Italy and France. During her study in France, she was the correspondent of Aftonbladet in Paris.
In 1878, she founded a school in Stockholm with Ellen Key, known later as the Stockholms nya samskola (New Co-educational School of Stockholm) and later as Whitlockska samskolan (Whitlock Co-educational School) or simply as the Whitlockska samskolan (Withlock School), and served as its principal from its foundation to 1918. This was a pioneer institution. The school was made co-educational in 1893, which was very progressive, as normally only primary schools for children were co-educational in Sweden at the time, and it became one of the first schools over primary educational level to be co-educational in Sweden. She also introduced innovations such as students councils, parent days, free choice of subject, voluntary education in religion and vacation colonies for school children. Because of the strict religious tolerance of her school, it became popular among non-Lutherans such as Jews. Her school was successful and was granted government support and the right to issue professional degrees.
Described as a liberal and updated character with modern progressive views, she was also active in politics, the public debate and reform. She was a member of the board in the Föreningen för religionsfrihet (The Freedom for Religious Liberty) for several years in the 1880s. She expressed her liberal views regarding religion as a speaker, and published a work on this issue: Skolans ställning till religionsundervisningen i Sverige och andra länder (The Position of the School regarding the teaching of Religion in Sweden and other nations). At that time, the subject of religion in school education normally only consisted of education of the student in their own religion, that of the state, and nothing else. Whitlock opposed this and made the subject voluntarily in her school. She was active as a speaker on geography at the Stockholms arbetarinstitut (Stockholm Workers Institution) from 1882 to 1897. She was also a member of the board of the Frisinnade kvinnor (Liberal Women) in 1914–1923.
Anna Whitlock is one of the leading pioneers of the women suffrage movement in Sweden. She was one of the co-founders of the National Association for Women's Suffrage. In 1902, two motions regarding women suffrage reform were presented to the Swedish Parliament. One was from the Minister of Justice Hjalmar Hammarskjöld, who suggested that married men be given two votes, as they could be regarded to vote in place of their wives as well. The other motion was presented by Carl Lindhagen, who suggested women suffrage. The Hammarskjöld suggestion aroused anger among women's rights activists, who formed a support group for the Lindhagen motion. On 4 June 1902, Föreningen för Kvinnans Politiska Rösträtt (FKPR) was founded: initially a local Stockholm society, it became a national organization the year after.
She was a member of the board and served as chairperson twice: in 1903–1907 and 1911–1912. She wrote the first public appeal to the women of Sweden to form a suffrage movement in the press, and she organized the rules of the association. She had a very good relation to her vice chairperson, Signe Bergman, and was respected for her ability to, though personally a liberal, maintain the political neutrality of the association. In 1911, when the suffrage movement was forced to make a political stand against the Conservatives, because their party was by then the only one to oppose women suffrage, the conservative Lydia Wahlström stepped down as chairperson: it was because of the respected ability to be neutral that Anna Whitlock was elected for her second term in office as chairperson in 1911.
In 1905, she founded the Cooperative association Svenska hem (Swedish Home) for women, which attempted to ensure better food quality. This association still exists today.
Anna Whitlock was given the Illis Quorum in 1918.
The Anna Whitlocks Minnesfond (Anna Whitlock Memorial Fund) was founded after her school was discontinued in 1976, and still grants scholarships to students.
The main character of the 2013 TV-series Fröken Frimans krig ("Miss Frimans war"), Dagmar Friman (portrayed by Sissela Kyle), was based on Anna Whitlock.