Though she was born in the U.K., actress Played spent her early childhood in Singapore and Hong Kong. As a trained singer and musician, she was discovered by a talent agent for her vocal range in a jazz band. She made her film debut in The Last of the Blonde Bombshells (2000), a U.K.-U.S. co-production about a woman (Judi Dench trying to reunite a swing band from WWII.

Garai portrayed the younger version of Dench's character. She then moved on to British television as office girl Zoe in the workplace drama Attachments and long-lost daughter Charlotte in the miniseries Perfect. She was cast as Kate Nickelby in Douglas McGrath's 2002 film version of Charles Dickens' Nicholas Nickelby. The film won Best Ensemble Performance from the National Board of Review. However, it was Garai's role as Gwendolen Harleth, the wife of Henleigh Grandcourt (Hugh Bonneville), in the BBC adaptation of George Eliot's Daniel Deronda that really proved she could do period pieces. The next year, she earned her first major starring role in Tim Fywell's independent romance I Capture the Castle, based on the book by Dodie Smith.

Garai played teenaged Cassandra Mortmain, a young woman living with an eccentric family in 1930s England. She earned a nomination for Most Promising Newcomer from the British Independent Film Awards. In 2004, she made her first American production with Dirty Dancing: Havana Nights. She stars opposite Diego Luna as young American girl Katey Miller, who moves to Cuba with her parents in 1958. Other projects for 2004 include Mira Nair's Vanity Fair starring Reese Witherspoon.