Despite leading Bayern to the Bundesliga title last season, Ancelotti was dismissed at the end of September after seeing his side beaten 3-0 in the UEFA Champions League by Paris Saint-Germain.
Reports claimed Ancelotti had lost the support of several key players in the dressing room and that contributed to his downfall, leaving Bayern chiefs with the task of replacing the experienced Italian.
And they have ultimately turned to a familiar face, with Heynckes returning to Bayern four years after he appeared to retire at the end of an historic treble-winning campaign.
Heynckes guided Bayern to Bundesliga, DFB-Pokal and Champions League success in his final campaign, making them the first German club to manage the feat.
The 72-year-old returns with Bayern five points adrift of league leaders Borussia Dortmund after seven matches.
It is widely reported that Hoffenheim's highly-rated 30-year-old head coach Julian Nagelsmann is being lined up to take the reins on a long-term basis at the end of the season.