She is known for her roles as the FBI agent Megan Reeves in the CBS television series Numb3rs, the firefighter Laura Miles in Rescue Me, and the division chief Sharon Leone in Fire Country.

[6] Farr was a co-host for 200 episodes of the advice program Loveline on MTV and made guest appearances on The Drew Carey Show, Arli$$, and CSI.

She portrayed the recurring role of Amy DeLuca, mother to the series co-star Majandra Delfino's character Maria, on The WB's and later UPN's Roswell.

[9] In April 2010, Farr had a role as Barbara, a mother whose negative influence led her son Eddie to become a serial killer, in a flashback episode of Desperate Housewives.

When Barbara discovered Eddie's collection of newspaper articles about the women he hurt or murdered, he strangled her to death.

[11] She also had a recurring role in the final season (2012–13) of the Grey's Anatomy spin-off series, Private Practice, as Miranda, a terminal cancer patient and the love interest of Dr. Sheldon Wallace (Brian Benben).