Walker was born in 1966 in Cheshire, England. Interested in the performing arts since childhood, she originally planned to be a dancer, but an injury when she was just 18 forced her to concentrate on acting. She enrolled at London's Drama Center and went on to the Royal Shakespeare Company. She took on a number of small stage roles before appearing on British television. Walker made a bigger splash in the Harrison Ford film, Patriot Games based on the Tom Clancy political thriller, where she played an English woman in an Irish terrorist group. She followed the role with a part as Vida, a mysterious neighbor, in the Sharon Stone sexy noir, Sliver in 1993. She has steadily worked in TV and films and will appear in Caprica for the Sci-Fi Channel in 2010.