News of the Easter weekend talks between Mike Pompeo and the reclusive Kim was the latest in a series of revelations from the US leader that have fuelled hopes of a major diplomatic breakthrough with Pyongyang.
Heaping praise on Pompeo -- the man he has already tapped to be the next secretary of state -- Trump said the 54-year-old's covert mission to the North Korean capital had gone well.
"He just left North Korea. Had a great meeting with Kim Jong Un, and got along with him really well, really great," Trump said. "He's very smart but he gets along with people."
Trump earlier tweeted that the "meeting went very smoothly and a good relationship was formed."
"Details of Summit are being worked out now," added the president, who is hosting Japan's Prime Minister Shinzo Abe for two days of talks at his Florida retreat, which he calls the "Winter White House."
Neither Trump nor the White House offered details of what was discussed and it remains unclear if there is enough potential for an agreement to have the Trump-Kim summit, slated for early June, go ahead.
Officials and outside experts say it is still not clear that Kim, who depends on the military to remain in power, is willing to completely give up his nuclear weapons.
North Korean talk of "denuclearization" -- which Trump has seemingly embraced -- has in the past been code for removing America's military presence on the Korean peninsula, something long unthinkable in Washington.
"Denuclearization will be a great thing for World, but also for North Korea!" Trump added in the tweet.
Nonetheless, the flurry of diplomatic activity has raised hopes for a pair of upcoming and potentially historic summits.
Kim is expected to meet South Korea's President Moon Jae-in next week for landmark talks at which discussion of a formal peace declaration is now on the cards.
The 1950-53 Korean War ended in an armistice rather than a peace treaty, leaving the two sides technically at war. The Demilitarized Zone between them bristles with minefields and fortifications.
Seoul's push to formally declare an end to inter-Korean hostilities would have been unthinkable just months ago.
"We are looking at the possibility of replacing the armistice regime on the Korean peninsula with a peace regime," a senior official at South Korea's presidential Blue House said Wednesday.
"But this is not something we can do by ourselves. It needs close discussions with relevant parties including North Korea."
But reaching any final treaty would be fraught with complications.
While the US-led United Nations command, China and North Korea are signatories to the decades-old armistice, South Korea is not.
Both Pyongyang and Seoul claim sovereignty over the whole Korean peninsula, but a treaty could imply mutual recognition of each other.
Next week's meeting will be just the third summit between the North and South since the armistice was signed 65 years ago.
Key moments including Kim and Moon's first handshake will be televised live, both sides agreed at working-level talks Wednesday, Seoul said.
US Summit By June
Trump himself plans to hold a summit meeting with Kim within the next two months.
The pair have not spoken directly, the White House said, but the president revealed Tuesday there had been contact at "very high levels" to prepare for the historic meeting -- an apparent reference to Pompeo's visit.
Trump also said that "five locations" were being considered for the summit.
"That will be taking place probably in early June or before that, assuming things go well. It's possible things won't go well and we won't have the meetings and we'll just continue to go on this very strong path we have taken."
US officials say that no decision has yet been made on a meeting venue, but China, North Korea, South Korea, and Panmunjom in the Demilitarized Zone are seen as possible locations.