He is an award-winning British television, stage, film and voice actor. He became popular with his interpretation of Stephen Hawking in the television film Hawking; as well as the role of the famous detective Sherlock Holmes in a modern adaptation of Sir Arthur Conan Doyle's character in the Sherlock series (2010-2017); both BBC productions. In 2015 he would receive his first Oscar nomination for Best Actor, for his role in the film The Imitation Game.
He is known for playing "Doctor Strange" in the Marvel Cinematic Universe films Doctor Strange (2016), Thor: Ragnarok (2017), Avengers: Infinity War (2018) and Avengers: Endgame (2019). He lent his voice to two main antagonists, the dragon "Smaug" and "the Necromancer", in the films The Hobbit: An Unexpected Journey (2012) and its sequels, he is also recognized for his role in Star Trek: Into Darkness.
In February 2011, he starred in the theatrical adaptation of Frankenstein at the Royal National Theatre opposite Jonny Lee Miller, for which he received an Olivier Award for Best Actor. In late 2011, he played "Major Stewart" in Steven Spielberg's War Horse (2011). He also played Peter Guillam in Tinker Tailor Soldier Spy (2011). In 2013, he played Julian Assange in the film The Fifth Estate, directed by Bill Condon.