Walger began her career on British television. In 1998, she guest-starred in an episode of ITV crime series, "Midsomer Murders". She had the recurring role in the BBC 1 sitcom "Goodnight Sweetheart" in 1999, and appeared in two episodes of the crime/drama "The Vice". Also in 1999, she played the daughter of newspaper magnate Max Van der Vuurst, Hilde, in the "Heat of the Sun" story "The Sport of Kings". The following year, Walger made her film debut in the biographical drama "Eisenstein". In 2001, she moved to the United States and was cast as Donna Barnes on the HBO comedy series, "The Mind of the Married Man". The series was cancelled after two seasons. In 2003, she starred on the short-lived U.S. version of "Coupling", which aired on NBC. In 2004, Walger played Nicole Noone opposite Noah Wyle in the TNT television film, "", for which she received Saturn Award for Best Supporting Actress on Television nomination.