She is married to Leonard Nimoy's son, Adam.
- Back to School (1986): Valerie Desmond.
- The Twilight Zone, episode "The After Hours" (1986): Marsha Cole.
- Hellraiser III: Hell on Earth (1992): Joanne "Joey" Summerskill.
- Quantum Leap, episode "A Leap For Lisa" (1992): Lt. Lisa Sherman.
- Star Trek: Deep Space Nine (1993-1998): Jadzia Dax.
- Becker (1998-2002): Regina "Reggie" Kostas.
- Ms. Fanservice: Dax was generally seen as the "sex symbol" of Deep Space Nine thanks to Farrell's considerable beauty. Also, her first scene in her Quantum Leap appearance has her walking naked on a beach and saying, "The ocean makes me feel so sexy!".
- What Could Have Been: She played the Cat in a pilot for an American version of Red Dwarf. The pilot was not picked up. If it had led to a series, Farrell would not have been available to play Dax.