Characterization
One of Lex’s key characteristics is his curiosity for the unexplained. Lex’s primary motive for his "shady" actions derives from his curiosity, specifically beginning from the moment he and Clark meet after Lex hits Clark with his Porsche. Clark always appearing when something strange happens in Smallville does nothing but fuel Lex’s curiosity. Rosenbaum believes that Lex’s only sees two options: "For Lex, it’s either take a nice ride to Metropolis and work with his dad, or find out what’s going on with this strong, strange fellow, Clark Kent." Another characteristic of Smallville’s Lex Luthor—one that is being developed over the course of the series—is his evilness. Rosenbaum believes that what the audience sees in Lex’s dark side in the early seasons is merely a taste of what the character is truly capable of. In the season two premiere "Vortex", Rosenbaum requested Greg Beeman to shoot a close-up of him after he shoots Nixon, in an effort to open a window into Lex's darker side. Rosenbaum intended to leave the interpretation of whether Lex enjoyed killing Nixon open to the audience. As Beeman explains Rosenbaum's thoughts, "...either Lex is horrified and appalled, or he liked it, and it felt good to him". According to Rosenbaum, when Lex reaches that point where he uses all of his mind, and "really flips out", that is the point where the "world needs to hide". Television reviewer Brian Byun felt that it was this struggle between good and evil inside Lex that not only made him an anti-hero, but also, given that the audience familiar with Lex's mythology and the knowledge that he will end up being Superman's greatest enemy, make Smallville's Lex Luthor a "tragic figure almost Shakespearean grandeur".
Taking a page out of Chazz Palminteri's A Bronx Tale, Rosenbaum ignored the script during his final scene with Kristin Kreuk for the season six finale. Here, as Lana is informing Lex that she is going to leave, Lex walks around her and closes the door to her exit. Rosenbaum was trying to invoke a moment of fright for the audience. To the actor, he wanted the audience to wonder what Lex was going to do to Lana; it was a moment meant to show just how unpredictable Lex can be.
Lex: Do you think I’d look better with hair?
Lana: I don’t know. I’ve never thought about it.
Lex: I’ve thought about it; I’ve thought about a lot of things….Clark has nice hair.
As the seasons progressed, and the character began to grow darker and more sinister, Rosenbaum sought more opportunities to bring humor to the scene, either with physical subtleties like little smiles at key moments, or "self-deprecating humor". One such instance, which became popular with audiences, was in the season six episode "Justice", where Lex made a joke about wanting a ponytail. The producers were concerned over the piece of dialogue, but Rosenbaum convinced them that he could pull it off. To Rosenbaum, this quip by Lex makes him more credible as a person, because it is well known that Lex always wanted hair. This moment reflects an earlier episode, where Lex reveals his feelings of meagerness when comparing himself to Clark. In season five's "Lockdown", Lex provides a window into his thoughts about his place in Smallville. As writer Steven S. DeKnight describes it, the audience gets to see a moment where Lex shows how he still feels like an outsider, and that he views Clark as this "perfect person". DeKnight believes that, from how Clark sees it, Lex is driven by his desire to attain everything that Clark has, like his family and girlfriend.
Lex also develops a craving for power, with that hunger expanding in season five. Al Gough believes that Lex’s political motivations are based on his lust for power. Rosenbaum echoes that opinion, believing that Lex can never get enough; "Lex is an insatiable character". Rosenbaum believes that nothing will satisfy Lex’s hunger, and that he will keep going until he is president of the United States. Even then, he will keep trying to make the majority of people like and believe in him.
Visually, the character of Lex Luthor has his own characteristics. In Smallville, Lex is usually given a "glass, steel background", and dressed in a lot of black, grey, and "cool tones" like purples and blues.
Read more about this topic: Lex Luthor (Smallville), Character Development