What Planet Is Lex Luthor From?

Lex Luthor is from Earth — specifically, he was born and raised in Metropolis (or Smallville in some continuities). Despite his genius-level intellect and obsession with extraterrestrial technology, Luthor is entirely human, which is actually central to his rivalry with Superman: he resents that an alien from Krypton is celebrated as humanity's greatest hero while he, a self-made human genius, is overlooked. In most modern continuities, he grew up in Smallville alongside a young Clark Kent before moving to Metropolis to build his empire.