[5] Swan was politically active in the First World War, and as a suffragist, a Liberal activist and founder-member and vice-president of the Scottish National Party.

Prime Minister William Ewart Gladstone wrote to The Scotsman that he thought it "beautiful as a work of art" for its "truly living sketches of Scottish character".

[9] Later successes such as The Gates of Eden (1887) and Maitland of Lauriston (1891) owed a debt to the fiction of Margaret Oliphant, who was among her critics, accusing Swan's novels of presenting a stereotypical, unrealistic depiction of Scotland.

[3] While writing for the British Weekly, she became acquainted with S. R. Crockett and J. M. Barrie, whose work like hers was given the unflattering epithet kailyard, an allusion to its parochialism and sentimentality.

[11] Swan used her maiden name for most of her career,[2][8] but occasionally the pseudonyms David Lyall and later Mrs Burnett Smith.

She wrote books and novels on the suffragist movement in Britain, often as David Lyall, such as Margaret Holroyd: or, the Pioneers (1910).

[12][13] The novel used interconnecting stories that followed a young suffragette, Margaret Holroyd, and dealt with many real problems faced by suffragettes and suffragists, such as disapproval of family and friends, fear of public speaking, physical exhaustion and ethical dilemmas in a rebellious, sometimes militant atmosphere.

They lived initially at Star of Markinch, Fife, where she befriended the Scottish theologian Robert Flint and his sister.

[7] While in London they became friends and neighbours with the writer Beatrice Harraden and with Joseph and Emma Parker at a later date in Hampstead.

[7] A collection of her personal correspondence, The Letters of Annie S. Swan (1945) edited by Mildred Robertson Nicoll appeared two years later.

Shortly after the Representation of the People Act 1918 gave women the vote in Britain, she was the first female candidate, standing unsuccessfully for the Maryhill division of Glasgow in the general election of 1922.

[24] After her defeat, the Women's Freedom League claimed that Swan and other female candidates would have been elected under a system of proportional representation like those in Ireland, Netherlands and Germany.