SEOUL, South Korea — When Kim Jong-un made his debut as the North Korean heir apparent in September 2010, he looked so much like his grandfather, the closest thing North Koreans had to a god, that South Korean intelligence officials noted that many North Koreans who saw the young man for the first time on television broke down in tears.

“The regime wants its people to see Kim Jong-un as Great Leader Kim Il-sung reincarnated,” said Kim Kwang-in, head of the North Korea Strategy Center, a research organization based in Seoul that collects information from sources inside North Korea. “They fattened him up and gave him a thorough training — and plastic surgery, too, some even say — to make him look just like his grandfather.”

Since his elevation to leader after the death of his father, Kim Jong-il, in December, Kim Jong-un has been presenting himself as a near replica of his grandfather, Kim Il-sung — from the way he clapped his hands, walked with shoulders thrown back and stood tall with a paunch, down to such details as his double-breasted greatcoat, high-trimmed sideburns, double chin and full cheeks.

The packaging of Mr. Kim as the embodiment of the North’s widely revered founding president suggests that a well-oiled machine is at work to create a new leader. The strategy of having Mr. Kim assume his grandfather’s persona, and relying on nostalgia for the “Great Leader” to justify and consolidate his dynastic succession, reflects the slightness of the young leader’s own résumé, as well as the length of his grandfather’s and father’s shadows, under which he must rule....