She broke into mainstream television in 1993, with a guest appearance on the collegiate drama, Class of '96. As a result of this, she was cast as Special Agent Dana Scully in the X Files, which ran for 9 seasons and included two films, released in 1998 and 2008. She had roles in a handful of films during the run of The X-Files and starred in The House of Mirth, an adaptation of the Edith Wharton novel of the same name. When The X-Files ended, she performed in several stage productions and worked on various film projects. In 2005, she appeared as Lady Dedlock in the BBC TV adaptation of Charles Dickens' novel Bleak House, had a starring role in the Irish film The Mighty Celt and performed in A Cock and Bull Story, a film version of the novel Tristram Shandy. During 2006 and 2007, she appeared in two British films: The Last King of Scotland (2006) and Straightheads (2007).