Kearney lifted the title with the Dubliners in 2009 when he came off the bench against Leicester in the 19-16 victory, while the 25-year-old then played in the semi-final defeat to Toulouse last season.
However his chances of starring in the Heineken Cup this season - and taking on Northampton Saints in the final - have been ruined by a serious knee injury suffered playing for Ireland against New Zealand.
And Kearney, who has seen Isa Nacewa shine at full-back in his absence, told skysports.com: "It is hugely frustrating to miss out.
"It is always difficult to be on the sidelines when your team-mates are chasing silverware but at the same time you would rather have your team going for trophies than not at all."
Northampton, though, stand in Leinster's way - and Kearney knows his side will have to raise their game when they go head-to-head with the likes of Soane Tonga'uiha, Ben Foden, Chris Ashton, Dylan Hartley and Courtney Lawes.
But having learnt some harsh lessons from the 26-16 defeat to eventual winners Toulouse in 2010, Kearney is confident Leinster will able to combat the threat posed by the Saints.
"It is going to be a huge test against a very good side," said Kearney, who has been making good progress back from the knee surgery he underwent in November.
"I think they are a very good across the board. We know they've been challenging in the top four of the Premiership all season and they have a really strong scrum and a talented back three.
"But when you look back to the semi-final last season, we were against a side with a dangerous back three in the shape of Toulouse and we kept them quiet, so it is just a case of being aware of the threat.
"Their scrumming capability is enormous, but I think that if there is one area we have improved on in the last year has be here.
"We got blown away by Toulouse upfront last year, so we have gone away and been work hard to improve. We have done and we will have plans in place for Saturday."
Optimum Nutrition (ON) is the Official Sports Nutrition Partner of the Leinster Rugby Team. For more information on ON and their range of premium sports nutrition products, go to www.optimumnutrition.com/uk
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