Actors portraying an unknown character

This category contains articles about the actors who portrayed an unknown character in the franchise of Smallville. While the end credits usually listed the guest actors for each episode, it does not state which character each actor or actress portrayed. While this information can sometimes be found on IMDB, the information is not always there (leaving a blank space) or accurate (examples include Lindsay Bourne (a man) being credited on IMDB as portraying "Moira Sullivan" in Scare, Alex Sparling and Brian McBride both being listed as "Alumni Guest" in Homecoming, with Ash Lee being listed as portraying a "Production Assistant" in the same episode). Note: if an actor's role is identified, their article (along with the individual episode article) is to be updated with the information (and the article removed from this category).