Judge Dominique Pauthe found Kerviel, 33, guilty of computer hacking and breach of trust and said that his actions threatened the bank's existence, Bloomberg News reported.
Kerviel has admitted that he exceeded trading limits and lied to his co-workers, but said that his superiors were aware of his actions.
When Societe Generale announced the loss in 2008, the bank's then-CEO Daniel Bouton described Kerviel as a "terrorist."
Kerviel plans to appeal the ruling.
"Prison is unacceptable for a man who didn't make a penny," Olivier Metzner, Kerviel's lawyer, said.