As of 2018, this is the seventh adaptation during the decade to be based on Sherlock Holmes lore, after: Sherlock (2010), Sherlock Holmes (2009), Sherlock Holmes: A Game of Shadows (2011), Elementary (2012), Mr. Holmes (2015) and Sherlock Gnomes (2018).
Speaking on the Empire Podcast #346 (11 January 2019) about the quality of the film, Steve Coogan, who played Gustav Klinger, said "I think in 20 year's time when the dust has settled and people are able to look at Homes and Watson objectively, I think people will say 'It's still rubbish".
Ralph Fiennes is now the fifth actor to play Professor Moriarty who has previously worked for Director Steven Spielberg. Paul Freeman (Without a Clue (1988)) and Anthony Higgins (Young Sherlock Holmes (1985)) appeared in Raiders of the Lost Ark (1981). Andrew Scott appeared in Band of Brothers (2001), and Jared Harris appeared in Lincoln (2012).
Ralph Fiennes' breakout role was in Schindler's List (1993), where he worked opposite Sir Ben Kingsley. Kingsley played Dr. Watson in Without a Clue (1988). He also appeared in James Bond films as M, a character previous played by Bernard Lee, grandfather of Jonny Lee Miller, who plays Sherlock on Elementary (2012).
Ralph Fiennes and Steve Coogan have both played the role of Hades in two separate Greek Myth movies, with Fiennes in the 2010 remake of Clash of the Titans along with its sequel Wrath of the Titans, while Coogan portrayed him in the movie adaptation of Percy Jackson and the Lightning Thief.
Rebecca Hall, who appears in this movie, co-starred with two actors who have previously played Sherlock Holmes. She was in Starter for 10 (2006) with Benedict Cumberbatch, who played the role on Sherlock (2010), and in Iron Man 3 (2013) with Robert Downey Jr., who played the role in Sherlock Holmes (2009) and Sherlock Holmes: A Game of Shadows (2011).
The North American and European cuts of the film have different openings. In the North American cut, Holmes and Watson meet each other at high school when they are teenagers. In the European cut, an adult Holmes accidentally saves an adult Watson from committing suicide.