According to DVD commentary, Tom Welling was known to wander around the set muttering under his breath, "Clark is an idiot! He is such an idiot!"
Jensen Ackles, who played Jason Teague in season four, was the second choice to play Clark Kent. If Tom Welling had not accepted the part, the role would have gone to him
Tom Welling (Clark Kent) and Allison Mack (Chloe Sullivan) are the only actors to appear in all ten seasons.
The characters of Chloe Sullivan (played by Allison Mack) and Whitney Fordman (Eric Johnson) were created specifically for the show (they were never mentioned in the Superman/Superboy comics). Though, in the Christopher Reeve's Superman films, Lana Lang had a boyfriend named Brad Wilson, who's also a high school football player. Also, a similar character named Bradley "Bash" Bashford appeared in the original Superboy comics. With the surname Fordham, Whitney was portrayed by Robert Gerdisch in the live-action film, Man of Steel (2013) where he is a fellow classmate of Clark, Lana and Pete Ross. He is also a football player for a Smallville team known as the Smallville Spartans and is known to help bully Clark. Prior to the film's release, that version of Whitney also served as the prime antagonist of the novel Man of Steel: The Early Years Junior Novel. Meanwhile, in 2003, DC Comics announced that Chloe Sullivan would be introduced into the Superman comics when she was officially introduced into the mainstream DC Universe on September 29, 2010, with her appearance in Action Comics #893.