After the two political gatherings, Jong-un, who had already gained the wartime military title of the supreme commander shortly after his father's death, took control of major military organizations.
They are the Ministry of People's Armed Forces, the General Political Bureau and the General Staff of the Korean People's Army, all of which are now headed by his closest aides.
The Ministry of People's Armed Forces, the equivalent of Seoul's Defense Ministry, is headed by Vice Marshal Kim Jong-gak, a member of the party's politburo.
Vice marshal is "chasu" in Korean, and a rank higher than a four-star general.
The General Staff of the Korean People's Army, an equivalent of Seoul's Joint Chiefs of Staff, is led by Vice Marshal Ri Yong-ho, dubbed Kim Jong-un's military tutor.
Choe Ryong-hae, a longtime aide to the Kim dynasty, has been picked to lead the General Political Bureau.
He is the first civilian in decades to lead the powerful military organ under the direct control of the party.
The bureau leads the crucial personnel management of other military bodies such as the Ministry of People's Armed Forces.
Choe was recently made an army vice marshal.
He rose up the political pecking order on the back of his father's close ties with the Kim dynasty.
His father Choe Hyon was a key member of the partisan guerrilla campaign against the Japanese colonialists in the 1930s, which was led by the communist state's national founder Kim Il-sung.
Becoming one of the five members of the decision-making politburo presidium of the party and the vice chairman of the party's CMC, he is now seen as one of the most powerful figures in the North.
The rise of Choe in the military signals that civilian elites such as Kim Kyong-hui, younger sister of Kim Jong-il, and her husband Jang Song-thaek, will flex considerable muscle in the management of field military units, experts noted.
Kim Kyong-hui is now the party's secretary while Jang is the vice NDC chairman. Both are four-star generals without military field experience.
While Choe came to the forefront of the regime in Pyongyang, experts believe that Kim Kyong-hui and Jang may continue to wield considerable power behind the scenes while advising Jong-un.
Some say that they might have elevated the status of some high-profile figures outside the Kim family such as Choe to avoid criticism that could flare up should there be any policy flip-flops.
Despite renewed emphasis on the party's role in state governance, the NDC is expected to remain a powerful organ that executes military-related and other key directives from the ruling party.
With the power succession process complete, Kim Jong-un now faces a set of challenges to maintain power, enhance economic conditions through normalizing ties with South Korea, the US and other nations, and have people coalesce around him.
There has still been a flurry of speculation over how Kim Jong-un is holding up as a leader of the reclusive state.
The prevailing theory appears to be that he makes final state decisions after consulting his aides.
Experts concurred that for the time being, it is unlikely there will be any big changes in the North given that interested parties, including Kim's inner circle, will want to maintain the status quo.