Farr was signed as an undraftedfree agent by the Los Angeles Rams out of the University of Washington in 1994. He had his best season in 1995 when he recorded 11.5 sacks and 1 interception. Farr recorded 8.5 sacks in the Rams' 1999 Super Bowl season.
After his playing career ended, Farr became a regular on the sports talk show The Best Damn Sports Show Period on Fox Sports Net. He has remained on FSN as a co-host of the network's college football coverage.
From 2005 until September 2007, Farr hosted the D'Marco Farr Show with Kevin Kiley on KSPN in Los Angeles.