He survived years of purges after Kim Jong Un took power, and has weathered a series of ups and downs in his standing.
"I'd have to see what the deal is", Trump said at the White House during a meeting with South Korean President Moon Jae-in, when asked about a partial deal.
South Korea's spy agency said in 2017 it believed he was behind the punishment of General Hwang Pyong So, once one of Mr Kim Jong Un's most-trusted advisers.
The ROK president said his "important task" now is to "maintain the momentum of dialogue" and "express the positive outlook, regarding the third U.S. -DPRK summit, to the worldwide community that this will be held in the near future".
He had been director of cultural exchange programmes and vice chairman at the Kim Il Sung Youth League in the 1980s, leading youth delegations on goodwill visits to China, Russia, Japan, Libya and Greece, according to database North Korea Leadership Watch.
"[The North Koreans] now probably are going to lose faith that President Moon can have any sort of influence inside Washington", Gause said.
"Now peace has prevailed", he said. He continued, "Moon is left caught in between".
Trump's mention of holding back on increasing sanctions appeared to be a reference to a tweet he sent last month saying he was withdrawing new measures aimed at North Korea that were just issued by his own administration.
Talks between Moon and President Trump suggest the U.S. isn't open to making any concessions, however. He said great progress was made and that he got to know and respect the North Korean leader.
The official news agency also said Friday that Kim Jae Ryong was chosen as premier of the cabinet, replacing Pak Pong Ju.
Moon has been acting as a go-between to resolve the nuclear standoff and has worked aggressively to foster better relations between the North and the South and keep nuclear talks between the United States and North Korea moving. South Korean business owners who operated factories in the Kaesong complex from its opening in 2004 until it shut down in 2016 have been anticipating the opening of the industrial park. I didn't think it was necessary.
"Sometimes you have to walk", Trump said, slipping into his real estate dealer's lingo, after the Hanoi meeting.
Trump said he would favor easing those sanctions at the right time but added: "This isn't the right time".
Pyongyang is "trying to undermine sanctions without agreeing to the current denuclearisation demand from Washington, while also improving its diplomatic strategies", analyst Ahn said.
Trump added that he remained focused on a more comprehensive agreement, though he did not rule out a "smaller deal". "You can work out, step-by-step pieces. But right now, we're talking about the big deal.to get rid of the nuclear weapons". Trump, however, reaffirmed his stance to maintain sanctions on Pyongyang to force it to give up its nuclear weapons program.