Her father was born in Czechoslovakia, the son of Jewish survivors of the Holocaust. Her mother converted to Judaism.
Her older brother Jake was the lead singer of the band Bluejuice and her sister Elana is a jazz singer and pianist.
The youngest of three children.
Her mother is a nurse and her father is an architect.
Yael is Hebrew, meaning ''God's strength''.
In a relationship with Jack Manning Bancroft since 2017. They have a daughter together, Pemau Stone Bancroft (b. May 30 2018).
She chose not to have a Bat Mitzvah ceremony when she turned thirteen.