Mattsson was born in Åsele, Västerbotten County, Sweden, on 17 February 1914. She grew up on a farm outside Åsele where she sometimes milked the cows. At some point, she got a job as a maid in the district of Östermalm in Stockholm.

When she was around 102 years old, she moved into a nursing home. When asked for advice on living a long life at the age of 105, she replied: “Eat normal home cooking, sleep and live as usual.”