Blewett was born Janet McKinshie in Scotia, Kent County, Ontario in 1862 to Scottish immigrants (some sources say 1872). She attended St. Thomas Collegiate and in 1879 married Bassett Blewett and published her first novel, Out of the Depths. In 1896, she won a $600 prize from the Chicago Times-Herald for her poem "Spring".
Blewett was a regular contributor to The Globe, a Toronto newspaper and in 1898 became editor of its Homemakers Department. In 1919, assisted by the Imperial Order of the Daughters of the Empire, she published a booklet titled Heart Stories to benefit war charities. During this time she regularly lectured on topics such as temperance and suffragism. She used the pseudonym Katherine Kent for some of her writing.
In 1925 Blewett was compelled by ill-health to retire her editorship. For two years she lived with a daughter in Lethbridge, Alberta, before returning to Toronto in 1927. She died in 1934 in Chatham, Ontario.
After her death, fellow female journalist Bride Broder wrote in tribute:
There is a simplicity about Mrs. Blewett's prose and verse that has made a wide appeal, and her gay-hearted attitude to life, the humorous twists she gave to little things, made her very welcome as a speaker at women's gatherings. In all her writings she touched on the things that appeal to women everywhere and, in doing so, won the admiration of men readers also.
- 1879 or 1890, Out of the depths (novel)
- 1897, Heart Songs (collected poetry)
- 1906, The Cornflower and Other Poems (collected poetry)
- 1919, Heart Stories (collected stories)
- 1922, Jean Blewett's Poems (collected poetry)
- Campbell, Sandra; McMullen, Lorraine (1991). New Women: Short Stories by Canadian Women, 1900-1920. University of Ottawa Press. pp. 139–140. ISBN 9780776603230. Retrieved 16 December 2012.
- Gerson, Carole (2002). "Blewett, Jean McKishnie". In New, W. H. Encyclopedia of Literature in Canada. University of Toronto Press. p. 128. ISBN 9780802007612. Retrieved 16 December 2012.
- "Writer Honors Jean Blewett". Calgary Daily Herald. Canadian Press. 19 August 1934. p. 14. Retrieved 16 December 2012.
- Garvin, John William (1916). Canadian Poets and Poetry. McClelland, Goodchild & Stewart. pp. 190–196. Retrieved 16 December 2012.
- "Jean Blewett, authoress, dies". The Leader-Post (Regina, Saskatchewan). 20 August 1934. Retrieved 16 December 2012.
- Sources differ on the publication date for this novel.