Moon sees the Games as an opportunity to restore regular communication with North Korea and eventually pull it into talks over resolving the worldwide stand-off over its nuclear programme.
The recent detente, anchored by South Korea's hosting of the Winter Olympic Games, came despite an acceleration in the North's weapons programme previous year and pressure from Seoul's allies in Washington.
When he was returned to the United States, he had horrific brain injuries which his family attributed to him being tortured by the Kim Jong Un's regime.
South Korea's President Moon Jae-in waved and smiled, as did IOC President Thomas Bach, as the Korea athletes marched together with two flag-bearers together. The unified Korean team also marched together in a lovely display under a unification flag but the show stealer was Pita Taufatofua-who competed in taekwondo in Rio's Summer Games and is in Pyeongchang to compete in cross-country skiing-for reprising his bare-chested appearance as flag bearer for Tonga.
The US has imposed sanctions on North Korea over the latter's nuclear weapons development.
"I leave here very confident that we are going to continue to do the things we've known have to be done to continue to pressure North Korea to abandon their nuclear ambitions".
"And it also is a signal that North Korea is not this insane, weird former Cold War state - but it too has young women that are capable and are the future leadership". The sight of North and South Koreans marching together for the first time in a decade was the culmination of months of work by Seoul.
Even as the two Korean families met in the Blue House, anti-Pyongyang protests were being held.
Trump's lookalike sported a red U.S. baseball cap while Kim's imitator made sure he looked like the North Korean leader by wearing a black spectacle and a black coat.
But according to CNN, Pence and Moon did not discuss the invitation or the summit, with the Vice President instead telling reporters that he "spoke as friends" with the South Korean leader.
Later on Saturday Ms Kim, Kim Yong-nam and Moon Jae-in attended the first ice hockey match played by a unification team of athletes from both North and South Korea.