Rosenberg was born on 17 May 1984 in Brighton to Quaker parents, English mother Jane and American Jewish father, Gerard Rosenberg, originally from Vineland, New Jersey. Rosenberg learned classical guitar at a young age and at around 14–15 started to write songs. He did not apply himself at school in Brighton, spending his time making music. Rosenberg left school at the age of 16 to pursue a career in the music industry and spent the next few years as a busker in England and Australia.

Rosenberg did his first performance when he was 16. Rosenberg’s father, a film production worker, introduced him to former member of the band Faithless, Jamie Catto, in 2001; this led to Rosenberg getting a two-song spot at the Free Burma Campaign benefit gig at the Royal Court in London in 2002. On the night, Rosenberg met his future writing partner Andrew Phillips and established contact with the IE Music label. Back in Brighton, Phillips and Rosenberg pooled their musical influences (from Simon & Garfunkel to DJ Shadow), and started to write songs at Phillips’ in-house studio in Hove. In 2003, they formed the Mike Rosenberg Band, engaging Marcus O’Dair (bass), Alon Cohen (drums) and Richard Brinklow (keyboards) through connections within the Brighton music scene. (Wikipedia)