Portrayal in the series
Smith is a knowledgeable biologist and cunning villain who is largely identical to his Canon counterpart, albeit with a few departures from the source material. The person he killed before Holmes started investigating the case is depicted as his cousin, not his nephew, as in the original story. In a more major divergence from Doyle's short story, Smith is apprehended on the spot at 221B Baker Street by doctor Watson, while the Canon version was successful in committing suicide by cutting himself with a sharpened object infected with the illness he used for the murders.
Smith's personality has the surface of a polite, reserved gentleman and highly professional medical expert, but his cold-bloodedness hides a ruthless and heartless streak. To further his own personal goals, he is not above committing covert murder by infecting his clients with rare and deadly diseases.
Culverton Smith only appears in the second episode of The Memoirs of Sherlock Holmes, "The Dying Detective", much like his literary counterpart.