Jude Royce's Imposter was a minor character from the First Season of Smallville, appearing in the episode "Zero". He was an unnamed man who was hired to be him.
Real Jude Royce
The real Jude Royce was the fiancé of Amanda Rothman and a friend of Lex Luthor. In 1999, Lex took Amanda to Club Zero as his escort. Unfortunately, Amanda catches sight of Jude across the room sitting between two beautiful women. Jude correctly guesses that Lex brought her there on purpose but Lex admits that Amanda deserves better.
While still at the club, Jude catches up with Lex and they exchange blows with Jude pulling out a knife and stabs Lex in the shoulder. Max Kasich pulled out his gun, but a dancer bumped him and he dropped it and Amanda picked it up and shot Jude.
Following the incident, Lex called upon Sam Phelan to write up a different story of events, stating that Max shot Jude whilst fulfilling his duty to protect Lex and Amanda.
Three years later, Jude Royce had seemingly returned from the grave and had come to Smallville seeking revenge against Lex. Jude first went to The Talon and applied for a position as an assistant manager. Jude warns Lana Lang that whatever Lex gets involved with usually turns out badly.
When he learns that Jude has applied for the assistant manager position he becomes upset and leaves. He then stalked and harassed Lex's former security guard Max demanding the truth about Amanda's death. Jude then murdered Max and sent his hand to Lex in a gift box.
While working out in his gym, Lex remembered the night Amanda died and as the memory ends, someone puts a gun to his head. When Lex turns around, he sees Jude Royce, the man who should be dead. Clark arrives at the mansion and scares Jude off.
Jude later framed Lex for illegal waste dumping on the Kent family's farm. Lex is on hand to supervise the cleanup, but one of the CEP men is Jude Royce. He uses a taser gun to shock Lex and throws him into an empty cargo van. He drives him all the way to Metropolis, to the abandoned site that was once Club Zero, puts him a straight jacket and hangs him from his heels, ten feet off the floor.
Here, Jude planned to force Lex to admit that he had shot him. Before Lex could, the imposter was shot by the true mastermind behind Lex's humiliation: Roy Rothman. Roy revealed that "Jude Royce" was a look-alike and an ex-con in need of money and was all too willing to help Roy with his plan to destroy Lex, so he assumed Jude's identity.