In 2006, he collaborated with DJ Mark Ronson, to cover the Radiohead song, "Just". The cover appears on the compilation album "", as well as the Mark Ronson album, "Version". He appeared with Ronson at the 2007 Glastonbury Festival where he climbed up on to the lighting rig of the John Peel stage during the performance of "Just", and also sang "California". In 2010, he collaborated once again with Ronson on the album "Record Collection", on which Greenwald shares writing credits on six out of the eleven tracks. He became part of Ronson's band, The Business Intl. for this record. He was also a member of Los Angeles band blackblack, until 2007. At live shows, he was known for 1980s styled dance moves, which were inspired from watching David Byrne of the Talking Heads.