Haines was born in 1972. His father, Kevin, played jazz bass, and his brother, Joel, played guitar. Haines played gigs with Joel across New Zealand, before moving to New York in 1991 to study jazz music.Haines received classical training on flute and saxophone. His father Kevin Haines, being an accomplished acoustic bassist, exposed his son to jazz music – particularly Miles Davis, John Coltrane and Thelonious Monk.