Cook was born in Minneapolis, Minnesota to Thomas H. Cook, a social worker and former stand-up comic, and JoAnn, a cooking instructor and weaver. Cook attended school at Clara Barton Open, Laurel Springs School and Minneapolis South High School. She began working as a print model at the age of 10, most notably in nationwide advertisements for Target and appearing on the boxes of Milk-Bone dog biscuits Read more...

At the age of 14, Cook began auditioning for acting work. Her modeling agency sent her to read for a short film, 26 Summer Street (1996). She first gained national attention when she was featured in a This is Your Brain on Drugs public-service television advertisement, in which she proceeds to destroy a kitchen with a frying pan as she lists the things that heroin harms (in 1998). Cook began her Read more...

Cook has dated actors Ben Foster, Thomas Montgomery, Vincent Kartheiser, Ryan Reynolds, Shane West, Rider Strong, Jonathan Rhys Meyers and Colin Hanks. She is now married to actor Daniel Gillies. Cook, a vegetarian, lives mostly in Los Angeles with her three dogs, but frequently goes back to visit her family in Minnesota.