Wearing his trademark Mao-style black suit, Kim disembarked from his olive green armoured train surrounded by a crush of security and aides as the guards presented arms.
Emerging from the station, he was met by a military band and a swarm of press that had waited overnight in the rain for his arrival.
He was quickly ushered into a waiting black Mercedes-Benz, his arm emerging from a rolled-down window to wave to crowds before briefly stopping in front of a group of students in school uniforms gleefully brandishing North Korean and Vietnamese flags.
Twelve bodyguards jogged alongside Kim's car as he left the train station, believed to be en route to Hanoi and a highly-anticipated second summit with US president Donald Trump over Pyongyang's nuclear arsenal.
Kim's motorcade of 20 or so cars took to the road after his brief swing through the normally sleepy Dong Dang train station in northern Vietnam -- a stone's throw from the China border -- which has been abuzz with activity in recent days.
Armed guards and sniffer dogs have been spotted at the station, which got a last-minute facelift with lick of fresh paint and new potted plants for Kim's brief welcoming ceremony on Tuesday.
In a last minute-scramble, a guard noticed some of the yellow-starred Vietnamese banners were upside-down and quickly righted them to avoid a diplomatic gaffe.
Joining Kim from Pyongyang was his sister Kim Yo Jong, one of his closest aides, who peeled off into a waiting car as her brother walked behind her waving.
Kim's de-facto chief of staff Kim Chang Son -- dubbed his "Butler" -- who has been in Hanoi for pre-summit preparations, was also seen at the station as Kim made his Vietnam bow.
- 'Strong message' -
This is Kim's first visit to the country, and the first time a North Korean leader has been here since his grandfather Kim Il Sung -- a close ally of Vietnam's revolutionary leader Ho Chi Minh -- travelled to the country in 1964.
Observers say he took the train to send a message to North Koreans -- and the world -- that he is falling in step with his grandfather, whom he frequently echoes in looks and mannerisms, and even his handwriting.
"It sends a strong message to North Koreans that Kim Jong Un has inherited his grandfather's good qualities, and the Kim dynasty is stronger than ever," said Koh Yu-hwan, a professor at Seoul's Dongguk University.
Kim will be hosted for an official state visit and is expected to visit two provinces to examine examples of Vietnam's post-war economic successes -- a glittering turnaround Washington hope Pyongyang can emulate.
One of those provinces is Quang Ninh, where Vinfast, Vietnam's first homegrown car manufacturer is located. The other is Bac Ninh, home to a Samsung factory, one of Vietnam's leading investors and top exporters.