Following several auditions, independent film roles, and guest-roles in television series, Blair achieved her breakthrough opposite Sarah Michelle Gellar and Ryan Phillippe in the 1999 coming-of-age drama Cruel Intentions, loosely based on the 18th-century novel Les Liaisons Dangereuses.
She starred with Jared Leto and Jake Gyllenhaal in the crime drama Highway, which was released directly-to-DVD in March 2002.
Her film career continued with the independent drama Kill Me Later opposite Max Beesley.
She starred as a suicidal bank teller taken hostage during a bank robbery, who tries to persuade her captors to kill her.
She subsequently appeared in several independent and short productions, including Debutante, opposite Josh Hartnett.
The short drama was shot in NYC and won multiple awards after its premiere in September 1998.