Michael Rosenbaum returns to Smallville for its finale. As seen here, he reprises the role of Lex Luthor.
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Lux Luthor will return for the final episode of Smallville. The character is played by Michael Rosenbaum.
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A picture of Michael Rosenbaum as Lex Luthor on Smallville. He was a major character until season seven.
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Smallville Quotes

I'm about as real as it gets.

Chloe

Clark: My father says you learn more about yourself when you lose.
Lex: What'd you learn?
Clark: That I'm not destined to be a politician. You need two different personalities.
Lex: You don't need to be an elected official to change the world, Clark.
Clark: Have you ever thought about getting into politics?
Lex: Someday I'd like to be president.