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Three Rock's 9-1 rout of relegated Instonians wasn't enough to deprive Banbridge of the title with the Down club having a three-goal advantage.
Fraser Mills and Matthew Bell both hit two goals for Banbridge with Ross Beattie and Eugene Magee also scoring.
Banbridge will aim to complete a men's treble in next weekend's play-offs.
The double winners will face Monkstown in the semi-finals at the Three Rock Rovers-hosted competition next weekend with the hosts playing Lisnagarvey in Saturday's other last-four encounter.
Either Cookstown or Annadale will replace relegated Instonians in next season's IHL after reaching Sunday's promotion play-off final in Dublin.
In the semi-finals, a second half Mark Crooks goal gave Cookstown a 1-0 win over Leinster champions Corinthian.
Annadale then defeated Munster side Bandon 5-0 with two goals from Peter Caruth and one each from Craig Getty, Matthew Crookshanks and Ben Wallace.
So Cookstown will face Annadale in Sunday's final, with the winners promoted automatically and the losers having a second bite at the cherry in a play-off with UCD to decide the final spot in next season's national league.
Lurgan Ladies are also trying to get into the IHL, in their case via a round-robin promotion play-off series.
They've started well with two wins out of two to go top of the table overnight.
Lurgan began with a 3-0 win over Connacht side Greenfields, two of the goals coming from Chloe McCann after Tara McIlwaine had broken the deadlock.
In their second game of the day, Lurgan defeated Trinity 3-2 with Sarah McClure hit a first-half hat-trick.
On Sunday, Lurgan are in action against UCC and Old Alex, needing to finish top to qualify for the IHL while second place would secure them a play-off with Belfast Harlequins.
Banbridge added the Irish Hockey League title to their Irish Cup triumph as a 6-1 win over Railway Union saw them pip Three Rock Rovers on goal difference.