Born on Oct. 4, 1979 in Minneapolis, MN into a solid middle class family, Cook began modeling at age 10 for Target and Milk-Bone dog biscuits campaigns. While attending Minneapolis South High School, the ambitious teen began auditioning for acting roles, making her film debut in the short, "26 Summer Street" (1994) and gaining national notoriety for a memorable public service announcement for the Partnership for a Drug-Free America, which produced the famous This Is Your Brain on Drugs ads. In her PSA, Cook demonstrated the debilitating effects of heroin on mind, body and family by smashing an egg in a frying pan before destroying the entire kitchen, ending the ad with the famed tagline, “Any questions?” Cook made the jump to features, playing Mary Anne in the film "The Baby-Sitter's Club" (1995), based on the popular children's book series. That same year, she co-starred as Becky Thatcher in "Tom and Huck,” an adaptation of Mark Twain's classic novel starring Jonathan Taylor Thomas and Brad Renfro. An auspicious beginning with impressive performances unfortunately led next to a role in the forgettable "Carpool" (1996).

Continuing to amass credits, she delivered a small turn in the twisted indie comedy, "The House of Yes" (1997), playing the ubiquitous Parker Posey's obsessed Jackie-O as a child. In 1998, the young actress costarred in "Strike!/The Hairy Bird,” a teen comedy set in the 1960s about a girls' boarding school fighting the admittance of boys and featuring such up-and-comers as Kirsten Dunst, Gaby Hoffmann and Monica Keena. As the mischievous and mean-spirited Abby Sawyer, Cook played a part quite unlike her previous good girl roles. Later that year, the busy actress appeared in "Living Out Loud” as the teenaged Judith, as portrayed by an adult Holly Hunter. She starred as a rape victim fighting for custody of her son in the CBS drama, "Country Justice" (1997) and essayed the younger version of Angelina Jolie's character in the miniseries "True Women" (CBS, 1997) – a period piece about the women who helped settle Texas. Cook earned favorable notices as a traumatized assault victim in Showtime's "The Defenders: Payback" (1997), and while the role of the quiet and withdrawn girl called for little dialogue, she capably conveyed the character's emotional fragility.

Cook continued to rack up more film credits, this time in lead roles. As the title character in the teen comedy "She's All That" (1999), featuring Freddie Prinze, Jr. and Anna Paquin, she starred as a bespectacled high school nobody who a popular boy bets he can turn into a prom queen. The film was a runaway hit and advanced Cook and Prinze, Jr. to A-list status. Cook was next featured in "The Bumblebee Flies Anyway" (1999) with Elijah Wood, and starred in "The Hi-Line" (1999), a drama about an adopted girl searching for the truth about her origins. While she was wasted as a computer programmer in the pallid thriller "Anti-Trust” (2001), the actress led the pack as an aspiring rock singer and de facto leader of a girl group in "Josie and the Pussycats" (2001). Having formed her own production company, Ben's Sister Productions, Cook added a co-executive producer to her resume with the unreleased indie thriller, "Invisible Girl" (2001).

Cook’s talent was wasted in “Blow Dry” (2001), an overblown romantic comedy set in the world of the National Hairdressing Championships where the more outlandish and hair-sprayed styles win the day. In “Texas Rangers” (2001), an earnest but ultimately failed western about the forming of the famed group of lawman, Cook starred as the daughter of an aging sheriff who falls in love with one of the Rangers (James Van Der Beek). After a role in the bank heist comedy “Scorched” (2002), she appeared in “Tangled” (2003), a revenge thriller about a young man (Shawn Hatosy) who pieces together for police the savage beating that landed him in the hospital, including his involvement with his now-missing girlfriend (Cook) and obsessive roommate (Jonathan Rhys Meyers). She then starred in the coming-of-age drama “Stateside” (2003), playing a schizophrenic singer in love with a rich but lonely teenager (Jonathan Tucker) whose mutual love endures despite his forced entry into the Marines and her admittance to a mental institution.

Cook continued appearing in low-budget features, though given the quality of the finished product, an astute observer would have questioned why. In “Bookies” (2003), she played a college student wooed by a small-time bookie (Nick Stahl) who uses his newfound wealth to impress her. Then after a supporting role in the sci-fi noir “The Big Empty” (2003), Cook appeared as a waitress in the indie thriller, “29 Palms” (2003), about a drifter (Jeremy Davies) who steals a bag of money and is hunted down by a hit man (Chris O’Donnell) hired by the owners of a Native American casino. Cook next appeared in the French-made “Tempo” (2004), a run-of-the-mill heist picture in which she played a jewelry store clerk with access to the safe who is approached by an antique smuggler (Hugh Dancy) to rob the store. She followed up that film by playing an inexperienced reporter who discovers she is the target of a serial killer in the straight-to-video release, “American Crime” (2005).

While her onscreen roles seemed to lack the promise after “She’s All That,” Cook went back to a suddenly more respectable small screen, starting with the epic miniseries, “Into the West” (TNT, 2005), playing a young woman who forges her own way in an unforgiving land. After an appearance on the sketch variety show “Weekends at the D.L.” (Comedy Central, 2005) and an episode of the animated satire “Robot Chicken” (Cartoon Network, 2004- ), she landed a recurring role on the hit primetime drama, “Las Vegas” (NBC, 2003- ) playing a real estate agent who falls into a steamy affair with Danny McCoy (Josh Duhamel), understudy to the head of security (James Caan) for the fictional Montecito casino. Returning to features, Cook co-starred in “Nancy Drew” (2007), the long-awaited adaptation of the famed teen mystery novels, playing the rightful heir of a murdered film star (Laura Elena Harring) killed decades before, whose death is solved by a quirky tweener detective (Emma Roberts) newly relocated to Hollywood High.