Hesselgren was born at Torsåker, Gästrikland. She was the daughter of medical doctor Gustaf Alfred Hesselgren and Maria Margareta Wærn. She was the eldest of six children. She never married. She was educated by a governess at home and then at a girl school in Switzerland. In 1895, she graduated as a feldsher in Uppsala; in 1896. The following year she led the School of Domestic Science in Stockholm. Whilst on leave she qualified as a Sanitary Inspector from Bedford college in 1905 and left the college and her job in 1906.
Early career
Kerstin Hesselgren worked as a sanitary-inspector in Stockholm 1912-1934 and school kitchen inspector 1909-34. Hesselgren had originally wished to be a physician, but her weak constitution had made her regarded unfit for this profession. Instead, she educated herself for the profession of Sanitary Inspector, to be able to focus on better health conditions through inspection and improvement of the living conditions in the capital, which were at that time appalling for the working classes. She did manage to introduce improvements, which made her respected in political circles. She was chairperson of the Swedish school teacher's society 1906-1913. She was management director of the women's work environment inspection from 1913 to 1934. In July 1925, Hesslegren attended and spoke at the First International Conference of Women in Science, Industry and Commerce held in London, organised by Caroline Haslett and the British Women's Engineering Society. From 1906 onward, she received a number of political assignments.
Politician
Hesselgren was given the Illis Quorum in 1918, and in 1921 she became one of the five first women to be elected to the Swedish Parliament after women suffrage alongside Nelly Thüring, Agda ÖstlundElisabeth Tamm and Bertha Wellin in the Lower chamber. Hesselgren was alone in the Upper chamber and thereby became the first woman in the Upper chamber. She was a liberal in 1922–23 and 1937–44 and Independent in 1923–1937. Until 1934, however, she formally labeled herself as belonging of no particular party in parliament, because she had been elected with the support by two parties. She was Vice Chairman of the second legislation committee of the parliament in 1939–1944, and also in this capacity the first of her gender in Sweden. Kerstin Hesselgren, being the first of her gender in parliament, regarded herself to be the spokesperson of females in the Upper Chamber. Hesselgren was active within gender and social issues: she worked for the access of all political positions and equal salary for both sexes, for the legalisation of sex education and birth control and to lower the punishment for abortion. She was well known and aroused a lot of attention to these issues. Many of her ideas was inspired by her mentor, the politician Emilia Broomé, and could be found already among the ideas of Bromée. Hesselgren died in Stockholm at the age of 90. The University of Gothenburg established the Kerstin Hesselgren Visiting Professorship in her memory. It is awarded to outstanding female researchers in the social sciences or humanities.