He is best known for his roles as Denethor in The Lord of the Rings film trilogy (2001–2003), and Dr. Walter Bishop in the Fox science fiction series Fringe (2008–2013).

[1] In 1979, he starred in Errol Flynn's Great Big Adventure Book for Boys at the Edinburgh Festival in Scotland.

He won awards when starring as eccentric scientist Walter Bishop in the television series Fringe for 5 seasons (2008–2013).

He voiced the Dragon Spirit in M. Night Shyamalan's film The Last Airbender (2010), appeared as Real Estate tycoon Leland Monroe in Rockstar Games' L.A. Noire (2011),[3] and provided the voice for Unicron in the animated series Transformers: Prime and its conclusion film Transformers Prime Beast Hunters: Predacons Rising.

Noble has done voice-over work for numerous DC Comics projects, including the animated film Superman: Unbound (2013) as the supervillain Brainiac, the video game Batman: Arkham Knight (2015) as the primary antagonist Scarecrow,[4] and the television series Legends of Tomorrow as the demon Mallus.