Noble lives in the US with his wife Penny Noble. They have three children: Daniel Noble, Jess Noble and actress Samantha Noble. In 2011, John Noble's hobbies are reported to be "music, painting and narration". He studies theoretical physics, and requested that the writers of Fringe always keep things grounded in what could be scientifically feasible. Noble starred as scientist Walter Bishop in the television series Fringe. He made occasional appearances on the television series All Saints. He is internationally known for his performance as Denethor in The Lord of the Rings trilogy. He played Russian Consul Anatoly Markov in the sixth season of the American television series 24. In 2011, he appeared as Real Estate tycoon Leland Monroe in Rockstar's video game L.A. Noire. He is also the voice of Unicron for the television show Transformers: Prime and its conclusion film.