His owner Philip Reynolds described the 10-year-old as a 'horse of a lifetime' in an emotional tribute.
Presenting Percy producing a scintillating display in the 2018 RSA Chase - his second Cheltenham Festival success, having won the Pertemps Final 12 months earlier.
He went on to win a second Galmoy Hurdle the following season, but could finish only eighth when favourite for the Cheltenham Gold Cup, and never quite managed to rediscover his former brilliance.
After moving from Pat Kelly's yard to Gordon Elliott last summer, however, Presenting Percy got back on the winning trail when beating multiple Grade One winners Kemboy and Monalee in a Listed event at Thurles - his 11th career victory.
An eighth-placed finish in the Savills Chase at Leopardstown over Christmas proved to be his final start - as he was ruled out of Cheltenham and later the Grand National at Aintree because of a leg infection, which ultimately cost him his life.
Reynolds said: "It's with great sadness I have to confirm that we lost a three-month battle against infection and have had no option but to put Presenting Percy to sleep.
"I want to thank Ger Kelly and his staff at Fethard Equine Hospital for all their efforts in trying to save him and allow him the retirement he deserved.
"I know it's a cliche to say racing is a game of highs and lows, and we've had our share of both, but on days like this it makes you wonder if the highs are high enough.
"Percy was a special athlete with a personality all of his own. He took us places we dreamt of, and we always looked forward to having him with us during his downtime.
"We are deeply hurting at his loss and feel so sorry for so many connected with him - Tom Costello, from whom I bought Percy, Pat Kelly, Kim and the team who made him, Gerry and all in Athenry who loved him, Gordon Elliott, Mary and the crew at Cullentra, and of course (jockey) Davy Russell - who gave our family three memorable Cheltenham days, two with our star Percy.
"The sudden sadness of his passing is hard to contemplate, and the wonders of 'what if' will remain. To everyone who shared our love for Percy, we are so sorry.
"The horse of my lifetime - and my honour to have been called his owner."