She was born in the year 1676, most likely in Alsters parish, Värmlands county.
By the time she got married to Pär Månsson in 1711, they both were living at the farm Forsnäs in Alsters parish.
Kierstin lived at the farm Nothern Forsnäs until 1747, when the family moved to the farm Hösserud in the same parish. Two years later her husband Per died, and she became a widdow. The farm was then taken over by their son Swen.
She lived at Hösserud until she died, 76 years old, on November 1 1766. She was buried on November 7.