Rohullah Nikpa won a bronze medal in the men's -68kg category on Friday morning, marking Afghanistan's first medal in London 2012.
Nikpa overcame Britain's Martin Stamper 5-3 in the bronze medal match.
The 25-year-old became a national hero after winning Afghanistan's first ever Olympic medal four years ago in Beijing. It's the second-ever Olympic medal for Afghanistan.
"Of course, getting a medal is very important to all the countries in the world but especially for Afghanistan," Nikpa said.
"I'm very happy because this medal is very important for my country."
He lost out to Iran's Mohammad Bagheri Motamed in the quarter-finals in London but took advantage of a second chance through the repechage.
He beat David Boui of the Central African Republic 14-2 before beating Stamper in the semi-final.
Afghans back home remained awake throughout the night to watch Nikpa's matches and to celebrate the victory, even through posting comments and congratulation notes in the social media.
One called Nikpa a "sports hero", arguing his country needs more of this rather "war hero". "It's a big change in Afghanistan and creates hope," posted Wahid Waissi on Facebook.
Another Afghan taekwondo hero Nesar Ahmad Bahawi is facing his test today as millions of Afghans at home are expecting thier flag to be raised again.
In other games, the Afghanistan athletes lost in judo, athletics and boxing competitions.