"Having comrade Kim Jong-il at the highest post of our country again is a great honour and happiness," a newscaster said on state-run television.
Mr Kim, 67, has ruled the impoverished nation of 24 million with absolute authority since his father's death in 1994.
Mr Kim's suspected stroke last August kept him out of the public eye through a series of important anniversary events, and is believed to have caused a delay to the parliamentary elections.
In recent weeks, North Korean media have released video images of Mr Kim touring farms and factories, in what analysts say was a strategy designed to show he was fit and well before the parliament vote.
Some observers suggest that even Sunday's rocket launch was timed for maximum propaganda value ahead of the parliamentary session.
Mr Kim was confirmed in his third term as the country's leader
Analysts say Mr Kim received a domestic boost from the launch, despite widespread foreign criticism of what was seen as a disguised missile test.
State television broadcast a lengthy paean to Mr Kim on Thursday, a day after tens of thousands of North Koreans rallied in Pyongyang to celebrate the rocket launch.
But the UN Security Council has been debating whether North Korea should be punished.
Japan and the US are pushing for a UN Security Council resolution which would reinforce and possibly extend existing sanctions against North Korea, applied in the wake of the country's nuclear test in 2006.
But China and Russia have been more cautious, saying they are yet to be convinced Pyongyang broke any rules.
North Korea has warned that "strong steps" will follow if the UN does takes action.
A recent report in North Korea's communist party newspaper said Mr Kim was "choked with sobs" that the money spent on the launch could not be used for the people's basic needs - but added that they would understand.
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