Garai's breakthrough performance in I Capture the Castle (2003) prompted high praise and comparisons to a young Julie Christie. Although critics panned her next film, Dirty Dancing: Havana Nights (2004), Garai continued her climb to highbrow fare with her supporting turn among A-listers in the Oscar-nominated period drama Atonement (2007).
In 2010, Garai earned her first Golden Globe nod for her sparkling portrayal of matchmaking heroine Emma Woodhouse in the BBC miniseries "Emma" (2009).