Yoo Ji-Tae did not receive an Oscar nomination for portraying Lee Woo-jin in Oldboy.
Yoo Ji-Tae's casting and his performance offer quite an atypical villain for the film, as he first off he just does not look like this truly sinister man just by a glance then there is Yoo's portrayal. Yoo does not try to exert an overt menace with his performance, and again in fact there is this certain friendliness at times, though in reality more of a familiarity that Yoo expresses. Yoo does not do this to undercut his performance, no instead it amplifies in the way he creates this truly unique antagonist with Lee. That familiarity ends up being rather off-putting in one way Yoo alludes to the way that Lee knows so much that Dae-su does not, far too much in fact. There is even more though as Yoo suggests something even deeper than that even. Of course this also becomes duplicitous as Yoo makes that smile get under your skin as there is an innate smugness that Yoo brings, which again goes further than just making him this smug snake. Yes that is there, but again Yoo makes it seem all the more sinister since the smugness suggest his complete control of every situation in the film, and is imposing in his own way by creating Lee as this man who almost seems impossible to decipher while he apparently has everything deciphered around him.
Yoo, despite being very consistent in creating this sense of certainty in Lee, he is never one note. There are these brilliant edges he brings to his performance, moments that he uses so effectively to allude to more about Lee's nature and his real relationship with Oh Dae-su. These often are slight moments, where we see a real burning hatred, these are in small moments when he turns away for just a second, in those moments though are usually related to either when Oh Dae-su reveals absolutely no knowledge of why Lee is doing this to him, or later on when he begins to call back the memory. In those times though there is that intensity of a hatred, fitting to a man bent on revenge, yet Yoo takes it further as there a certain somberness in this anger reflecting his sorrow connected to the revenge. Eventually we do learn that Oh Dae-su caused a rumor, a true rumor, that Lee and his sister were having an incestuous relationship which eventually lead to her committing suicide. It is in the final confrontation where the film does reveal that it has always been about Lee's revenge, not Oh Dae-su's.
Lee brings throughout the scene that domination of what could be the noble avenger if it was not so twisted, as he breaks Oh Dae-su down with such confidence revealing his plan of revenge that entails Oh Dae-su unknowingly sleeping with his own daughter. The revelation causes a full mental breakdown in Oh Dae-su that leads him to beg Lee not to reveal the information to his daughter. Yoo is brutally effective by how he controls every moment and reveals what that satisfaction and familiarity came from. As Yoo presented as Lee knowing his plan was working but also conveying a certain connection through their mutual incest. Yoo is amazing in the final moment as he laughs over Oh Dae-su bringing such a joy in a man who has apparently gotten everything he desired, and essentially fulfilled what had become his life goal. Again though since this is his revenge story it ends as so many do in what is my favorite scene in this great performance. That being when Lee enters the elevator to leave Oh Dae-su alone in his misery with that smile of pure elation. Lee though hears recording of the pain of his actions which causes his mind to drift back to his sister's suicide which he was present for. Yoo is heartbreaking in his painful demise of that smile into such anguish, the anguish that is all he is left with after having avenged the death, which naturally leads to his own demise. Yoo Ji-Tae's performance here is outstanding piece of work as he successfully is so unlike what you'd expect from villain in a revenge film, yet also succeeds in creating this idea that Lee is living out his own revenge through his surprisingly poignant though still chilling portrait of a man consumed by vengeance in his own way.