There were mixed reports over whether Hong would stay on or quit in the aftermath of the Asian nation's exit in Brazil, as they accrued one point from three matches in Group H.
And on Thursday, the 45-year-old ended his tenure in charge of the senior side just over a year after it started.
"Today I'm here with heavy heart. I promised to give hope to fans before the World Cup but I have only disappointment after all. I feel really sorry," Hong said.
"I have managed the national team for about a year. Many things happened. I made many mistakes and faults. I made lots of controversies because I was not mature enough. I feel sorry for that too.
"I represented my country for 24 years as a player and a coach. Fans have supported me a lot. Today, I quit my duty for the national team. I will try to be a better person."
Hong said the reason his resignation came 14 days after their World Cup exit was down to him not wanting to jump ship and wash his hands of the responsibility of their exit.
"If I had announced it at the airport, I might have avoided some blame. But I felt that I should take it. So I hope you understand," he said.
"I made decisions myself about performance and technical decisions for the team.
"I thought they were for the best at that moment, but result was failure after all. I'd like to say sorry to the fans again."
Hong defended his decision to host a party for his playing squad, after their winless campaign.
"Players wanted to see Iguazu Falls but they gave it up as our results were bad," he said.
"So I wanted to console them with a little party as our young players were in so much grief.
"But I admit that it was not thoughtful to have a party."
Hong's reign saw him lead the Koreans to just five wins in 19 internationals.
