The national team started training on Wednesday and will play a friendly with Afghanistan in Ho Chi Minh City on June 1. Later, they will only have one big tournament left in 2022, which is the AFF Cup.
Vietnam won the AFF Cup in 2018 but lost to Thailand in the semifinals of AFF Cup last year.
"Our target is to reclaim the title at the end of the year," Park said.
Park is focusing on the national team now after a successful run with the U23 team at the 31st SEA Games, where they won the gold medal on May 22.
"In 2019, we won the first SEA Games football gold for Vietnam after 60 years. This year, SEA Games 31 was hosted in Vietnam and garnered huge attention. SEA Games 31 was also my final tournament as head coach of the U23 team. Therefore, this gold medal has a special meaning to me," Park said.
After the SEA Games final between Vietnam and Thailand, Park was seen crying and praying.
"I got emotional when I realized I had completed my goal. I also prayed as an act of showing gratefulness."
Park explained that huge pressure was a reason he wanted to leave the U23 team.
"I have been in charge of the U23 and national teams for over four years and faced many difficulties. I couldn't complete my job the way I wanted. I was under great stress during the preparation and huge pressure when I coached both teams. But now everything will be less difficult as I only focus on the national team."
Taking over Park's job at the U23 team will be Gong Oh-gyun, another South Korean coach.
"What I can do for coach Gong is share with him the experiences that I have accumulated during my time in Vietnam," Park said.
"That will point him in the right direction. But Gong also has his own tactics and football philosophy. I cannot interfere in his work. I respect him. We will help him adapt quickly to the football environment here," he added.