Which actor played Jim Moriarty in Sherlock?

Andrew Scott played Jim Moriarty in Sherlock.

Scott first appears as Moriarty in "The Great Game," the third episode of Sherlock's first series. The show reimagines Moriarty as a modern "consulting criminal," a criminal counterpart to Sherlock Holmes's consulting-detective identity. Rather than merely committing crimes himself, he sponsors, coordinates and manipulates other criminals while treating Sherlock as an intellectual obsession.

Moriarty becomes the central antagonist of series two. In "The Reichenbach Fall," he engineers an elaborate campaign to destroy Sherlock's reputation, posing as an actor named Richard Brook and persuading the public that Sherlock invented him. Scott's performance made the character unusually volatile and theatrical, helping distinguish this version from the more restrained Professor Moriarty of earlier adaptations.

Viewers sometimes confuse Scott with Mark Gatiss, who plays Mycroft Holmes and co-created the series, or with Lars Mikkelsen, who plays Charles Augustus Magnussen. Toby Jones appears in the later special "The Abominable Bride," but neither actor portrays Moriarty.