Gerhardsen was born in 1912 to Johan Werner Koren Christie (1879–1918) and Klara Rønning (1889–1967). She married Einar Gerhardsen in October 1932. They had a son Rune Gerhardsen and granddaughter Mina Gerhardsen. She is a sister-in-law of Rolf Gerhardsen. She was a member of Oslo school board, and Oslo city council from 1947. She was also a board member of the Norwegian National Opera and the Norwegian National Academy of Theatre, a supervisory council member of the National Theatre and a council member of Oslo Nye Teater.