Bergendahl was born in a small street in Gothenburg, Västra Götaland County on 10 December 1904, the youngest of four children born to a wholesaler Oskar Bergendahl and his wife Maria Nilsson. She had three siblings: Anna-Lisa, Karin, and Sixten. She attended Victoria School on Linnégatan, Haga School and Annedal School.

Through an acquaintance, Bergendahl acquired a position at a mortgage association’s bank, which she would retain until her retirement in 1964. She never married and had no children, and enjoyed travelling with her siblings. She remembered World War II as a “dark and troubled time.”

Bergendahl lived independently until the age of 102, when she moved into a Gothenburg nursing home. She voted in every election since 1921, when women were given the right to vote in Sweden, considering it her duty.

On 24 May 2014, aged 109, Bergendahl became Sweden’s oldest resident following the death of Karin Larsson. She became the oldest Swedish-born individual upon the death of U. S. resident Conrad Johnson on 23 December 2014.

Bergendahl died on 3 February 2015 at the age of 110 years, 55 days, with her successor as the oldest living person in Sweden being 109-year-old Rut Emriksson.