Leopold was a founding member of eclectic rock band Nojahoda who released one album on Sony
S2 Records in 1999. In 2003 he joined his brother
Atticus Ross, as well as
Bad Religion member
Brett Gurewitz in the punk/hardcore band
Error. Along with temporary vocalist
Greg Puciato, the band recorded and released a well received EP on
Epitaph Records in 2004. Around this time Leopold also began his scoring career, composing the music for the USA Network show
Touching Evil alongside Atticus Ross and Claudia Sarne. Leopold has since gone on to score numerous motion pictures and television shows, beginning in 2009 with the Hughes brothers' movie
The Book of Eli. In May 2010 this score won a BMI film music award. Outside of his scoring work, Leopold has written, recorded, produced and performed with various noted acts including
Bad Religion,
Grace Jones,
Korn,
Dillinger Escape Plan,
Rancid,
The Transplants,
Five Finger Death Punch,
Brigitte Fontaine,
The Big Pink,
Io Echo and
Brett Anderson. ==Personal life==