Frankfurt hit back just after the pause through Sebastian Haller. But five explosive minutes allayed the fears of the home faithful.
David Alaba restored Bayern's advantage after 53 minutes and substitute Renato Sanches made it 3-1 to launch the fest.
In came the Bayern veterans in the shape of 36-year-old Franck Ribery and 35-year-old Arjen Robben. The old lags didn't disappoint scoring the party piece fourth and fifth goals respectively on their final appearances for the club.
The title is coach Niko Kovac's second piece of silverware since taking over at Bayern last July after two years at Eintracht Frankfurt.
In August, Kovac led the Bundesliga champions - Bayern - to the German SuperCup with a 5-0 victory over the German Cup winners Eintracht Frankfurt
Borussia Dortmund finished the 2018/19 season in second place. Lucien Favre's men ended their campaign with a 2-0 win at Borussia Moenchengladbach. Jadon Sancho and Marco Reus scored the goals.
But there will inevitably be regrets for Favre and his band. They started the season in a storm. They clocked up 19 points from their first seven games.
But they began to falter in 2019. In February, they squandered a 3-0 lead to draw 3-3 with Hoffenheim. It was a month in which Dortmund won just one of its four Bundesliga games.
By early March, Bayern was back in first place and though Dortmund were not far behind, they could not recover.
Bayer Leverkusen exploited Borussia Moenchengladbach's defeat to snatch fourth place and the final berth from the Bundesliga for next season's Champions League.
Lucas Alario hit a hat trick as Leverkusen thrashed Hertha Berlin 5-1. Kai Havertz and Julian Brandt got Leverkusen's other goals.