Moynahan's talent and beauty combined with blockbuster films have established her as one of Hollywood's favorite leading ladies. She has starred in the feature film "Ramona and Beezus" and the sci-fi thriller "Battle: Los Angeles," and has appeared in numerous blockbusters, including "Lord of War," "I, Robot," "The Recruit," "Serendipity," "Unknown" and "The Sum Of All Fears." Moynahan first came to audience's attention in the film "Coyote Ugly." She also appeared in the independent features "In The Weeds," "Prey" and "Gray Matters."
On television, Moynahan portrayed Carrie's rival and Mr. Big's wife on "Sex and the City." Moynahan also starred in J.J. Abram's drama "Six Degrees."