Polachek was born in Manhattan, New York, on June 20, 1985.[2] Her family relocated to Tokyo, Japan, where she lived between the ages of one and six,[3] and later settled in Greenwich, Connecticut, where Polachek started singing choir in the third grade.[4] She was a synth player from a young age as her father gifted her a Yamaha keyboard to dissuade her from being disruptive on the piano.[5][4]