Dan Cole, Tom Croft, Geoff Parling, Manu Tuilagi, Ben Youngs and Tom Youngs all tasted glory with the Tigers, while Cian Healy, Jamie Heaslip and Brian O'Driscoll did the same with the Irish outfit who had also lifted the Amlin Challenge Cup just over a week ago.
Sean O'Brien and Rob Kearney were missing for Leinster but Ulster's Tommy Bowe and Northampton's Dylan Hartley suffered the agony of defeat just two days before Warren Gatland's tourists head to Hong Kong.
Tuilagi was among four Leicester try scorers in the 37-17 win over the Saints, for whom Hartley was sent off just before half time.
The England centre burst through from halfway to push Leicester 29-17 clear with 13 minutes left, giving Gatland a welcome reminder of his talents in the process.
Niall Morris, Graham Kitchener and Vereniki Goneva also crossed for Richard Cockerill's men as they picked up a 10th English title and made up for successive final defeats to Harlequins and Saracens.
Heaslip scored the second of two Leinster tries in a 24-18 victory to give departing head coach Joe Schmidt the perfect send off on home turf, with Sexton slotting four penalties and a conversion for a personal tally of 14 points in his last outing before leaving for France next season.
Ulster arrived in Dublin as top seeds but had opted to play the fixture down south as Ravenhill didn't meet the required capacity. Bowe and co failed to cross the Leinster line but were always in the hunt for a first league crown since 2006 thanks to the boot of Springbok scrum-half Ruan Pienaar.
Heaslip's try after 63 minutes proved decisive, though, as Leinster held off a late onslaught to bounce back from a hat-trick of heartaches at the final hurdle in 2010, 2011 and 2012.