With Park's current contract expiring at the end of next January, a fortnight after the AFF Championship concludes, the Vietnam Football Federation confirmed reaching a mutual agreement with Park to end their partnership then.
Although there is still a few months to go before Vietnamese football bids farewell to Park -- and one final chance for even more success -- the South Korean is already widely regarded as their greatest national team coach.
And it is hard to argue with his achievements.
In 2018, he ended Vietnam's ten-year wait to be crowned Southeast Asian champions again by leading them to their second AFF crown, ending Thailand's four-year stranglehold.
Before that triumph, that year had also seen him lead the Vietnamese to a runners-up finish at the AFC U-23 Championship and fourth place at the Asian Games.
Since then, under Park, Vietnam have also reached the quarterfinals of the 2019 AFC Asian Cup and claimed two consecutive Southeast Asian Games gold medals.
But perhaps his greatest achievement was leading Vietnam to the final round of Asian qualifiers for the FIFA World Cup for the first time ever -- effectively putting them among the continent's 12 best teams and in the same bracket as heavyweights such as Japan, South Korea and Iran.
Given none of his predecessors can boast such a long list of glowing achievements, it is understandable that the first question raised after Monday's announcement is whether or not this will spell the end of Vietnam's glorious era.
Already, there were signs of a slight decline -- or at least, a challenge to their dominance -- when Thailand reclaimed the last AFF Championship with the Vietnamese eliminated by them in the semifinals last December.
Yet, before the alarm bells start ringing in overdrive, Vietnam will continue to boast undeniable talent.
Vietnamese football has produced quality individuals even Park arrived, and they will continue to do so long after he has gone.
What has worked so well for Vietnam in the past five years is the fact that their once-in-a-century "golden generation" -- with a whole host of bright prospects all coming through at the same time -- coincided with the appointment of a savvy tactician, who was able to get them playing as a well-organised outfit perfectly drilled in the ways he knew could see them achieve success.
Even then, Park has not been immune to detractors for all his achievements.
A constant criticism of his reign has been a perceived defence-first mindset, understandable when Vietnam come up against the likes of Japan and South Korea but slightly questionable on the regional stage when they should be dominating teams such as Cambodia and Laos.
Park has never strayed from a five-man defence. While they can dominate possession in games, the Vietnamese still arguably look the most dangerous when hitting teams on the counterattack.
At last year's AFF Championship group stage, when Indonesia were content to sit deep with all 11 players behind the ball, Park's charges did struggle to find a way through.
So perhaps the mutual agreement to part ways will indeed be mutually beneficially for both parties.
Failure to win a second consecutive AFF Championship come next January would have raised further doubts over Park's tenure had he stayed on, and might even have risked tarnishing his legacy.
Now, he will either go out on a high or still be given the warmest of farewells from the Vietnamese football faithful who widely adore him as their 'teacher'.
And for Vietnam, maybe the only way to move on from what has undoubtedly been a glorious era is to take the next steps towards scaling even greater heights than the ones Park has already led them to.