Born in Worthington, Ohio, she went on to earn a Young Artist Award nomination in 2002 with her portrayal of 15-year-old murder victim Martha Moxley in the television movie Murder in Greenwich. In 2004, Grace was cast as Shannon Rutherford in the television series Lost, on which she was a main cast member for the first two seasons, winning a Screen Actors Guild Award shared with the ensemble cast. Leaving the series, Grace was keen to work more prominently in film. She appeared in The Jane Austen Book Club (2007), and opposite Liam Neeson as Kim Mills in Taken in 2008. She reprised the role of Kim in Taken 2 (2012) and Taken 3 (2014).