 Walker was born in Lower Hutt in 1982.She was raised by a mother on the Domestic Purposes Benefit and attended Waterloo School, Hutt Intermediate School and Hutt Valley High School, where she was deputy head girl.From 2001 she studied at the University of Otago, graduating with a BA (Hons) in English and Politics, as well as winning a Blue for her achievements with the Otago University Debating Society.