Chancellor had a prominent role in the series Kavanagh QC. She is also known for her performance as “Duckface” in Four Weddings and a Funeral opposite Hugh Grant. She has also been noted for her work as Caroline Bingley in the 1995 BBC adaptation of Pride and Prejudice, and as Questular Rontok in The Hitchhiker's Guide to the Galaxy. In 2005, she joined the cast of the popular BBC One television drama series Spooks as a new regular character, Juliet Shaw. She has also appeared in The Vice, Jupiter Moon, Karaoke, Cold Lazarus, The Dreamers, and Tipping the Velvet, and has a starring role in the satirical black comedy Suburban Shootout.