His grandfather made his name in the 1930s as a teenage guerrilla, battling the Japanese soldiers who then occupied Korea. His father spent decades solidifying the family's hold over the country, building up the military, extending the intelligence apparatus and driving its nuclear ambitions.
And Kim Jong Un himself? He apparently cut his teeth on the basketball courts of a Swiss middle school, a fiercely competitive player who posed as the son of a North Korean Embassy employee. Until, one day in 2000, he disappeared.
He wasn't seen again publicly until 10 years later, when he stood near his ailing father, Kim Jong Il, at a Pyongyang military parade. Cheering crowds greeted the baby-faced "Young General" as North Korea's ruler-in-waiting.
Now, with an outwardly seamless transition to the third generation of Kim family rulers, he appears to have been well-served by his competitive instincts.
In North Korea, everyone now knows who is in charge. Even if he probably isn't yet 30.
Deafening cheers greeted Kim Jong Un when he stepped onto a viewing platform Sunday and waved to tens of thousands of soldiers and civilians gathered in Kim Il Sung Square, the huge plaza named for his grandfather and the heart of the North Korean capital.
"We have been transformed from a small and weak country ruthlessly trampled upon by competing powers into a confident political and military power," Kim Jong Un said, the first time his voice had been heard here in public. "Our people are showing off their dignity as independent people who no one can dare provoke."
After Kim Jong Il's death, many observers had predicted the son would be little more than a puppet guided by his father's elderly inner circle.
But if it remains unclear exactly how much power Kim Jong Un wields, and how much he must share with the small coterie of relatives and advisers installed by his father, nearly all analysts say he has immense power.
In a week of events planned for the April 15 centenary of his grandfather's birth, a day celebrated as one of the greatest in the country's history, Kim assumed a series of top positions in the military, the ruling Workers' Party and the government.
"It's nonsensical to say somebody is pulling the strings behind Kim Jong Un," said Cheong Seong-chang, a North Korea analyst at the private Sejong Institute near Seoul, South Korea.
While the government-controlled media carefully nurture comparisons to his grandfather, portraying him as a smiling everyman who meets everybody from the political elite to low-ranking soldiers, he also shares his father's knack for confounding the U.S. and its allies.
Kim Jong Il was a master at using missile tests and nuclear research _ and then promises to scale them back _ to manipulate the West into providing humanitarian aid to the North.
The younger Kim, who is believed to be about 29 years old, is apparently doing the same thing, though analysts add that his long-term policies have not yet become clear. He faced a serious setback on Friday, when a rocket that North Korea said was carrying a satellite blew up shortly after liftoff, scattering pieces over the Yellow Sea.
Washington says the launch was a cover for testing ballistic missile technology, though North Korea says it simply wanted to put an observation satellite into space.
On Tuesday, North Korea's Foreign Ministry rejected U.N. Security Council condemnation of the launch and accused the U.S. of leading a campaign to deny the country's right to develop a civilian space program.
Kim's speech two days after the launch may have overstated North Korea's position in the world _ it remains a deeply impoverished nation, despite its nuclear and rocket research programs _ but it was also widely seen as a forceful statement about his control over North Korea. During his years in power, Kim Jong Il only spoke once publicly. And then very briefly.
Most of the basic facts about Kim Jong Un's life, though, remain clouded.
North Koreans are told he graduated from Kim Il Sung Military University and speaks several foreign languages, including English. But his age, marital status and even the name of his late mother _ said to be one of Kim Jong Il's wives, Ko Yong Hui _ have never been made public.
The little personal information to emerge about Kim comes mostly from former schoolmates in Switzerland, who in interviews with European news outlets remember him as a ferociously competitive basketball fanatic obsessed with Michael Jordan. For the most part, he kept his personal history a secret.
"One day, he did actually say to me, 'My father is the leader of North Korea,' but I just thought he was making it up," Joao Micaelo, a former friend, told Britain's Sunday Telegraph.
Most analysts believe Kim Jong Un was at least partially educated in Switzerland, though officials at the German-language school, located in a quiet Bern suburb, say they do not know for sure if the young man who went by the name Pak Un was actually Kim Jong Un. They only say Pak Un was a student from 1998 to 2000, when he was in grades six to nine.
In this heavily militarized, one-party state, questions about Kim family history are almost never raised in public. Questions about Kim Jong Un, particularly with outsiders, are invariably met with little more than fusillades of praise.
At a recent mass gathering in a Pyongyang stadium, thousands of North Koreans chanted his name over and over again, along with a promise to "defend you with our lives!"
Surrounding Kim Jong Un is a group of aging North Korean dignitaries, including a handful of relatives and a tiny cluster of top military and political officials.
The closest adviser, many outsiders believe, is Kim Jong Il's brother-in-law, Jang Song Thaek. He is married to Kim Jong Il's younger sister, Kim Kyong Hui.
Jang, 66, was given a series of high-ranking titles a few years ago so he would have "the leadership credentials to be the mentor" of Kim Jong Un, said Ralph Cossa, president of Pacific Forum CSIS, a Hawaii-based think tank.
Cossa said China, which has become North Korea's all-important patron since the fall of the Soviet Union, has indicated it is pleased by the close ties between the two men.
"The Chinese see the next generation _ the combination of (Kim Jong Un) and Jang Song Thaek _ as the best hope of North Korea moving in the way of Chinese-style reform," said Cossa, who said he has spoken to a number of Chinese officials who have met with the Pyongyang inner circle. "The Chinese have certainly cast their lot with them."
North Korea's political history, though, makes it clear that true authority rests with Kim Jong Un.
"The history and political culture of this place is that one person makes the decisions," said Victor Cha, a top White House adviser on North Korea under President George W. Bush. Decisions of national significance, he said in a telephone interview, have always been made by the Kims.
"We have to assume that he has folks around him who are advising him, and maybe even giving him different opinions. But there's only one person in control, and it has to be this young fellow."
Associated Press writers Hyung-jin Kim in Seoul, South Korea, and John Heilprin in Geneva contributed to this report.