Which actor plays Mycroft Holmes in the BBC series Sherlock?

Mark Gatiss plays Mycroft Holmes in the BBC series Sherlock.

Mycroft is Sherlock Holmes’s older brother and is portrayed as exceptionally intelligent, observant, and politically connected. Unlike Sherlock, he is usually described as preferring to avoid physical effort, relying on his reasoning and influence instead. The series presents him as a senior figure within the British government, although his exact official role remains deliberately vague.

Gatiss also co-created Sherlock with Steven Moffat and wrote several episodes. His position behind and in front of the camera made Mycroft an important bridge between the programme’s production and its fictional world.

The character is adapted from Arthur Conan Doyle’s Mycroft Holmes, who appears in stories including “The Bruce-Partington Plans.” In both versions, Mycroft’s intellect is treated as potentially greater than Sherlock’s, but his lack of interest in fieldwork makes Sherlock the more active detective.