An attractive actress who has worked consistently since childhood without ever becoming a star, Tunney appeared on stage in her native Chicago before hitting Hollywood in the early '90s. She landed guest spots on various TV shows and graduated to features quickly, often playing troubled outcasts who find their inner strength. Tunney alternated between TV-movies (J.F.K.: Reckless Youth), indie films (Niagara, Niagara) and wannabe blockbusters (Supernova) before upping her profile as a lawyer helping the brother of her wrongfully convicted ex-boyfriend during the first season of the action series Prison Break in 2005. She returned to TV in 2008 as senior agent Teresa Libson in The Mentalist.
- Began her acting career in commercials as a child in Chicago.
- Studied acting at the Chicago Academy for the Arts and at the Second City Players Workshop, also in Chicago.
- Wore a wig in The Craft (1996) because she shaved her head for her previous film, Empire Records (1995).
- Won the Best Actress-Cuppa Volpe at the 1997 Venice Film Festival for her role in Niagara, Niagara.
- Appeared with Luke Wilson in the music video for Tom Petty's 1999 single "Swingin'."
- Underwent five weeks of mountaineering training before filming Vertical Limit (2000).
- Appeared in the pilot episode of House as the patient of the week.
- Competed in the eighth tournament of Bravo's Celebrity Poker Showdown, losing to Jason Alexander in the Championship game.
- 1999, Independent Spirit Awards — Best Female Lead: Nominee
- 1997, Venice Film Festival — Best Actress: Winner
- Oscar Holly Marmet — Son
- Bob Gosse — Ex-husband
- Nicky Marmet — Fiancé
- Andrew Dominik — Ex-significant Other