Son, 26, went into the competition with special motivation to succeed.
Under South Korean law, all males under the age of 28 are obliged to undertake two years of military service.
A special dispensation for sporting stars, however, meant that Son would avoid a potentially harmful interruption to his career if he led South Korea to victory in the Games.
The winger duly complied, leading an Under-23 team to a 2-1 win in the gold medal match against Japan to land the top prize and win exemption from military services.
And as a token of gratitude, it has emerged that Son donated a sizeable sum to the South Korean military prior to the tournament.
"Son Heung Min called us by himself saying he'd like to make a donation for Korean soldiers and their families," Kookbangilbo, the army's official daily newspaper, revealed.
The daily also quotes Son as telling the armed forces, "I have been always thankful for their service to the country. Please use the money for them."
Son has made 74 appearances for his country at senior level to date, scoring 23 goals and appearing at both the 2014 and 2018 World Cup.
Son is now focusing on recovering his best form for Tottenham after his hiatus from domestic football caused by the Asian Games, which caused him to sit out a month of action at the start of the Premier League season.
The player has made five appearances in the 2018-19 Premier League, including two off the bench, and is still looking to open his account after so far failing to find the net during the current campaign.