Michael Rosenbaum is an American actor and podcaster. He is known for portraying Lex Luthor on the television series Smallville, a role that TV Guide included in their 2013 list of "The 60 Nastiest Villains of All Time".

Lex Luthor is a fictional character from the television series Smallville. He features from the pilot episode until the season seven finale, and has been played continuously by Michael Rosenbaum, with various actors portraying the character as a child or teen throughout the series. The character of Lex Luthor, first created for comic books by Jerry Siegel and Joe Shuster in 1940 as nemesis of Superman, was adapted to television in 2001 by Alfred Gough and Miles Millar - this is only the third time the character has been adapted to a live action television series. The character has also appeared in various literature based on the Smallville television series, none of which directly continues from or into the television episodes.