- Two of her great-grandfathers are NFL team founders. Art Rooney, founder of the Pittsburgh Steelers, is her mother's grandfather, and Tim Mara, founder of the New York Giants, is her father's grandfather.
- Fell in love with theater and acting after attending a performance of Les Miserables at age 9.
- Was accepted to New York University's Tisch School of the Arts but deferred attending due to her acting career.
- Got her big break with a supporting role in the 2005 Oscar-winning film Brokeback Mountain, in which she played Heath Ledger's daughter—despite being only four years younger than Ledger.
- Has sung the national anthem at New York Giants games, including the 2005 game honoring her late grandfather, former owner Wellington Mara; and the 2006 nationally televised season opener against the Indianapolis Colts.
- Missed attending the Pittsburgh Steelers' win in Super Bowl XL due to work in Los Angeles on an episode of 24. She has since included a clause in her contract allowing her to attend any Super Bowl games involving the Giants or Steelers.
- Is skilled as a dancer, mainly in jazz, tap and ballet.
- 2014, Emmy — Outstanding Guest Actress in a Drama Series: Nominee
- Jamie Bell — Husband
- Rooney Mara — Sister
- Wellington Mara — Grandfather
- Kathleen Rooney — Mother
- Doug Brown — Uncle
- Max Minghella — Ex-significant Other
- Tim Rooney — Grandfather
- Dan Rooney — Great-uncle
- John Mara — Uncle
- Chris Mara — Father
- Daniel Mara — Brother
- Conor Mara — Brother