The 41-year-old military officer finally struck the Olympic bullseye for Vietnam to deny Brazil an opening day title at the Rio Games.
Vinh fell into the arms of his coaches after his near-perfect final shot in the men's 10m air pistol.
He duelled with Sao Paulo-born Felipe Almeida Wu who had taken the lead after the penultimate round.
The Vietnamese history-maker claimed the title with a total points haul of 202.5. Crowd favourite Wu, almost 20 years his junior, took silver only .3 adrift.
If Vinh was feeling as proud as punch at finally ending a quest for his country that first began in Helsinki in 1952, he wasn't about to show it.
"I'm very lucky, it's the first gold medal in Vietnam's history, I feel very lucky, thank you everybody," he said at a press conference.
"Making this gold medal is a life memory, never forget this. Because (it is the) first time making a gold medal for Vietnam."
Wu, Brazil's first Olympic shooting medallist since 1920, praised his uplifting home support and said he hoped his performance would boost his sport's popularity in football-mad Brazil.
On winning the 2016 hosts' first medal of these Games, he added: "There are no words to describe how happy I am. We work very hard, and everything is worth the pain. Pain on my shoulder, pain in my back, but I will forget about all this pain now."
"It is just perfect. I hope that the sport of shooting becomes more popular in Brazil. I don't know how, but I hope people get interested for this sport and start to practise, and I think that is a good thing, to win a medal. I hope it will be good for shooting."
'Try, try, try'
Bronze went to Pang Wei, while South Korean defending champion Jin Jongoh trailed in fifth.
Jin had his head in his hands walking off after failing to replicate his heroics at London 2012.
He also won 50m pistol gold four years ago and will be hoping to turn around his form when he defends that title later in the competition.
The first of the eight finalists to be knocked out was the Nepalese-born Indian Jitu Rai.
Russia's representative Vladimir Gontcharov was next for the chop, followed by Italy's Giuseppe Giordano, Jin, and Juray Tuzinsky.
That left the stage clear for the three-cornered climax. Pang's exit setting up a tense face off between the two military men.
Wu had his partisan fans leaping out of their seats when he hit the front, but Vinh fired his 20th and final shot true and straight to nail it in the style of a worthy successor to Jin.
Vinh recounted: "The Brazilian shooter was very fast and stronger, but I think only 'try, try, try'. On the last shot I don't think gold or silver. I think only try."