Born in Beverly Hills, California, USA, O'Brien's music has been used by CBS Television Distribution since 1994 including on-air promotions for Dr. Quinn, Medicine Woman (1993), CBS Network News (1994), Walker, Texas Ranger (1996), and Murphy Brown (1996). In 1993 he wrote and performed the song "89 Lines" for the thriller Kalifornia and in 1996 the song "Killing Time" for the romance Bed of Roses. His work as composer includes the films Last Train Out (1993), Brights (1996), People of Reason (1997), Homeopathic ER (1999), and A Dull House (2004).