Heynckes revealed on Thursday that Bayern have asked him to return as manager for the rest of the season after the sacking of Carlo Ancelotti.
Heynckes possesses a prestigious reputation at the Allianz Arena forged on the foundation of prior successes - a new agreement would secure his fourth stint in charge of the Bavarian giants.
The former Real Madrid boss' last season at the Bayern helm, 2012-13, produced an unprecedented treble of Bundesliga, DFB-Pokal and Champions League glory, before he made way for Pep Guardiola to take over.
At the time, Heynckes said he had no intention of taking any more coaching jobs but at the age of 72, he is set to return as the oldest manager across Europe's big five leagues, usurping another recent appointment.
Roy Hodgson, Crystal Palace - 70 years and 58 days (as of October 5)
A managerial career which started in 1976 has taken in countries including Sweden, Switzerland, Norway, Italy, England, Denmark, Finland and the United Arab Emirates.
Appointed at Premier League strugglers Palace last month as a replacement for Frank de Boer, Hodgson is perhaps best remembered - unfortunately for him - for his spell in charge of the England national team.
During that time, the Three Lions lost out meekly to Italy at EURO 2012, failed to get out of the group at the 2014 World Cup and suffered the humiliation of elimination to minnows Iceland at EURO 2016, prompting Hodgson's immediate resignation.
Arsene Wenger, Arsenal - 67 years and 349 days
Despite guiding Monaco to the Ligue 1 title in 1988, Wenger arrived at Arsenal from Nagoya Grampus Eight in 1996 as a relative unknown.
In the 21 intervening years, the Frenchman has revolutionised the English game's approach to diet and fitness, while also leading the 'Invincibles' side of 2003-04 to the title without losing a match.
That was Wenger's third - and, to date, last - Premier League crown, while three FA Cup triumphs in the past four years have failed to conclusively silence Gunners fans who feel he has outstayed his welcome, which was extended by two years ahead of this season.
Luigi Delneri, Udinese - 67 years and 44 days
The oldest manager in Serie A, Delneri has spent almost all of his career, bar a short stint with Porto, in the Italian leagues.
Following spells with the likes of Roma, Palermo and Sampdoria, he took charge of Juventus for the 2010-11 campaign.
Things did not go to plan, however, as the Bianconeri struggled to a seventh-place finish and missed out on Europe, before Delneri was sacked.
He will have better memories of his first spell in charge of Chievo, whom he guided to Serie A for the first time in the club's history.
They qualified for the UEFA Cup in their maiden season in the top flight, earning Delneri the coach of the year award.
Claudio Ranieri, Nantes - 65 years and 351 days
The affable Italian had taken charge of some of Europe's biggest clubs, including the likes of Atletico Madrid, Chelsea, Juventus and Inter Milan, without much success.
A disastrous spell with the Greece national team had Leicester City fans fearing the worst when Ranieri was appointed in place of Nigel Pearson in 2015.
But the season that followed will go down in history as one of the greatest sporting triumphs, as the Foxes embarked on a scintillating run to a truly remarkable Premier League title win.
At 65, Ranieri is unlikely to ever scale such heights again in his career. But frankly, who cares?
Christian Gourcuff, Rennes - 62 years and 184 days
Back for a second spell at Rennes, Gourcuff is a man who takes comfort in the familiar - he has also enjoyed three stints at Lorient, the latter of which spanned 2003 to 2014.
Subsequently, he was appointed as Algeria's head coach, but failed to end their long wait for Africa Cup of Nations success with a quarter-final exit in the 2015 competition.
He led Rennes to a ninth-place finish in Ligue 1 last season, but has won just one of the opening eight matches of the current campaign.
Heynckes unlikely to overtake Schulz
Although he will be firmly established as the elder statesman of Europe's elite, Heynckes will have some way to go to become the Bundesliga's most senior manager.
That honour goes to Fred Schulz, who was 74 years and 184 days old when he took charge of his final match, a 2-0 defeat for Werder Bremen at Stuttgart in April 1978.