Sean O'Brien and Cian Healy scored first-half tries to put Leinster in charge and they sealed the victory with a penalty try and then late touch-downs from Heinke van der Merwe and Sean Cronin.
On top of this being the biggest winning margin in history, no side had scored as many points as Leinster's 42 and no side had ever scored five tries in a final.
Leinster were inspired by Brian O'Driscoll and fly-half Jonathan Sexton.
Ulster worked a try for Dan Tuohy but they could not stop Leinster from becoming only the second team - after Leicester in 2001 and 2002 - to successfully defend their European title.
Toulouse have won the Heineken Cup on four occasions but no team in the history of a tournament has enjoyed such sustained success as Leinster, who won the title in 2009, 2011 and now 2012.
Pienaar and Sextons exchanged penalties but Leinster's defence held firm, withstanding wave after wave of Ulster pressure until Kearney's clearance was deflected by Stefan Terblanche.
That allowed Andrew Trimble to run the ball back, Ulster moved it left and Wallace shovelled the pass wide for Tuohy to score his first Heineken Cup try and keep Ulster in the game.
Pienaar's conversion drifted wide and Leinster were soon back on the attack through Nacewa and Brad Thorn before earning a penalty which Sexton converted.
Terblanche was sin-binned for a frustrated dump tackle on Sean Cronin and Sexton slotted the penalty and celebrated with a punch to the air.
There was no way back for Ulster - but Leinster still had more to give.
The Leinster pack drove upfield, Dave Kearney burst through a couple of tackles and then exploited the overlap allowing replacement prop Heinke van der Merwe to charge over in the corner.
And Cronin applied the coup de grace with the record-breaking fifth try in the final minute as Leinster ran a shattered Ulster side ragged.
COMMENT RULES: Comments that are judged to be defamatory, abusive or in bad taste are not acceptable and contributors who consistently fall below certain criteria will be permanently blacklisted. The moderator will not enter into debate with individual contributors and the moderator’s decision is final. It is Belfast Telegraph policy to close comments on court cases, tribunals and active legal investigations. We may also close comments on articles which are being targeted for abuse. Problems with commenting? firstname.lastname@example.org