Two senior U.S. administration officials said this was expected and will likely pave the way for eventual transition of the son to replace his father.
Kim Jong Il's sister, Kim Kyong Hui, was apparently also promoted to general, according to the state-run KCNA news agency.
"This appears to be the first public mention of Kim Jong Il's son by the North Korean media," said Mike Chinoy, the author of "Meltdown: The Inside Story of the North Korean Nuclear Crisis."
Chinoy said the announcement was a step in laying down the foundation for a transition."It's significant that there was an explicit reference to him, and the position of general is a very senior one, obviously," he said.