Klinger has been a frequent consultant on projects involving Sherlock Holmes, vampires, and the like. He served as the unofficial technical adviser for Warner Bros. 2009 film Sherlock Holmes, reading the script at an early stage and counseling the director and actors. He filled a similar role for the sequel, Sherlock Holmes: Game of Shadows. Klinger also consulted on Enola Holmes for Legendary Pictures. He has read and commented on numerous comic-book scripts, including HarkerThe Complete DraculaThe Trial of Sherlock HolmesSherlock Holmes and the Liverpool DemonSherlock Holmes: Year OneSherlock Holmes vs. Zombies, and The Baker Street Irregulars and often reads drafts of Holmes- or Doyle-related film scripts and books prior to production/publication. In many instances, he has written introductions for these projects and assisted with publicity and marketing. He consulted with the EMP Museum in Seattle on an exhibit of horror film props, contributing materials on Dracula, and with USC on an exhibit on crime fiction. After one such project, a friend dubbed him “the world’s first consulting Sherlockian,” a title that he bears with pride (Holmes himself was of course “the world’s first consulting detective.”)

Klinger also lectures extensively on Sherlock Holmes and Dr. Watson, Arthur Conan Doyle, Dracula, Bram Stoker, H. P. Lovecraft, and the Victorian age. He has taught a number of courses on these topics for UCLA Extension. Klinger has travelled extensively as a public speaker on these topics, including programs in Istanbul, Transylvania, Toronto, and the House of Lords in London, as well as college campuses around the U.S.