Newsom grew up in the small town of Nevada City, California. She was exposed to music from a young age. Her father played the guitar and her mother was a classically trained pianist who played the hammered dulcimer, the autoharp and conga drums. She attended a Waldorf school where she studied theater and learned to memorize and recite long poems. From a young age Newsom wanted to play the harp. From her instructor, Joanna learned composition and improvisation. She learned to play on larger Celtic harps until her parents bought her a full-size pedal harp in the seventh grade. She studied composition and creative writing at Mills College in Oakland, California. While at Mills, she played keyboards in The Pleased.