Excluding his contributions to re-recordings of Ozzy's earlier material, Down to Earth is the only Osbourne studio album to feature bassist Robert Trujillo, who left to join Metallica in 2003. It was the first Osbourne album to feature drummer Mike Bordin, previously of Faith No More, though he had played live with Osbourne since 1996. Though he plays on the album, guitarist Zakk Wylde did not contribute as a songwriter for the first time since joining Osbourne's band in 1988, because many of the songs were written before Wylde rejoined the band. Osbourne's previous guitarist Joe Holmes was involved in the writing and Osbourne chose to use outside songwriters such as producer Tim Palmer and Aerosmith collaborator Marti Frederiksen.
"Working with Tim on this album reminded me of [late guitarist] Randy [Rhoads]", Ozzy remarked of Palmer. "If it hadn't been for him, there wouldn't have been an album ... He has incredible patience, just like Randy."