In "The Adventure of the Empty House", Sherlock Holmes looks up for biographical information about Sebastian Moran in his index of criminal biographies.

A devoted sportsman and highly skilled shot, he was author of the books Heavy Game of the Western Himalayas in 1881 and Three Months in the Jungle in 1884, and reportedly once "crawled down a drain after a wounded man-eating tiger".

Ultimately he is used solely for assassinations that required his peculiar skill with the rifle; Holmes mentions the killing of a Mrs. Stuart in 1887 which he suspects (but cannot prove) Moran was involved in.

Colonel Sebastian Moran was also the villain in Doyle's Sherlock Holmes play The Crown Diamond, written in the early 1900s but not performed until 1921.

When this play was adapted as the short story "The Adventure of the Mazarin Stone", Moran was replaced by 'Count Negretto Sylvius'.