Kim Jong Il's two other sons, Kim Jong Nam and Kim Jong Chol, have not been spotted.
Kim Jong Un made his public debut just last year with a promotion to four-star general and an appointment as vice chairman of the Central Military Commission of the ruling Workers' Party.
Earlier, state television also replayed images of missiles being fired and the April 2009 long-range rocket launch that earned North Korea strengthened U.N. sanctions. The U.S., South Korea and other nations called it a test for a missile designed to strike the United States; North Korea said the rocket sent a communications satellite into space.
North Korea's officials have pledged their loyalty to Kim Jong Il's son.
In an essay paying homage to Kim Jong Il on Wednesday, Workers' Party mouthpiece Rodong Sinmun said North Korea under his leadership had been "dignified as a country that manufactured and launched artificial satellites and accessed nukes," referring to the country's nuclear program.
"Thanks to these legacies, we do not worry about the destiny of ourselves and posterity at this time of national mourning," the essay said, carried in English by the Korean Central News Agency.
"Supreme leader of our party and people Kim Jong Un takes warm care of the people left by Kim Jong Il. Every moment of Kim Jong Un's life is replete with loving care and solicitude for the people," the essay said.
Wednesday's procession had a stronger military presence than in 1994.
Kim Jong Il, who ushered in a "military first" era when he took power, celebrated major occasions with lavish, meticulously choreographed parades designed to show off the nation's military might, such as the October 2010 display when he introduced his son to the world.