MAYNOOTH, June 30, 2013 (AFP) - Casey, 35 ended a two-year winless drought by holing a monster 60-foot eagle putt to win the event by three shots with a round of 67 for a 14-under par tally.
Dutchman Joost Luiten (74) and England's Robert Rock (71) finished joint second on 11-under par with Rock being runner-up for a second time in the event in four years.
Casey arrived in Ireland having slipped from number three in the world in mid-2009 to be lying a lowly 169th on the world rankings, and also missing the early part of the 2012 season after breaking his collar bone in a snow-boarding accident.
Now after his 12th European Tour success, and a first since capturing the 2011 season-opening Volvo Champions event in Bahrain, Casey has set his focus on breaking back into the world's elite as well as a place in next year's European Ryder Cup side.
"I'm absolutely thrilled as I always wanted a grandstand finish and I got one," said Casey in relation to his final shot.
"I've never holed a putt like that to win a tournament. I feel over the moon.
"Psychologically, this win is huge. It almost feels like a first win again, that kind of feeling.
"I have struggled with the confidence, and this is a huge relief, knowing that I'm moving in the right direction; that I've got great golf left in me for another ten plus years.
"This is a massive confidence boost.
"I can start thinking now of getting myself back in the top-50 on the rankings, the Ryder Cup next year and the goal also is still getting back on the PGA Tour.
"And this win makes my season easier in terms of planning. I was chasing a little bit the last couple of months trying to play everything, because I know I was playing quite well, and it just needed something to click."
Casey's win pushed him up from 81st to 27th on the Race to Dubai.
However he will pass up next week's French Open and the hope of securing one of the five places off the money list into next month's British Open.
Instead Casey will now have to win the July 11th starting Scottish Open to qualify and secure the last place into the following week's Open Championship at Muirfield.
Fourth and final round scores in the Irish Open at the Carton House course in Maynooth, Ireland, on Sunday (par 72, GBR & IRL unless stated):
274 - Paul Casey 68 72 67 67
277 - Robert Rock 69 66 71 71, Joost Luiten (NED) 67 70 66 74
279 - Pablo Larrazabal (ESP) 69 69 66 75
280 - Jose-Maria Olazabal (ESP) 68 69 71 72, Gareth Shaw 73 68 70 69, Shane Lowry 67 70 74 69, Rafael Cabrera Bello (ESP) 69 70 70 71, Alvaro Quiros (ESP) 72 68
68 72
281 - Peter Whiteford 71 68 69 73, Alejandro Canizares (ESP) 71 69 69 72, Jamie Donaldson 69 71 69 72, Danny Willett 73 68 71 69, Peter Lawrie 72 71 67 71
282 - Ricardo Santos (POR) 71 66 71 74, Jose Manuel Lara (Spa) 71 70 70 71, Gregory Havret (FRA) 74 70 68 70
283 - Soren Kjeldsen (DEN) 71 70 72 70, Marc Warren 69 75 67 72, Thomas Bjorn (DEN) 68 71 70 74, Simon Thornton 69 73 70 71
284 - Anders Hansen (DEN) 69 70 71 74, Ross Fisher 73 70 70 71, Scott Henry 74 64 69 77, Raphael Jacquelin (FRA) 69 69 70 76, Brett Rumford (AUS) 72 71 69 72, Andy Sullivan 72 72 67 73, Eddie Pepperell 71 69 74 70, Richard Sterne (RSA) 73 70 67 74
285 - Richard Bland 71 72 70 72, Oscar Floren (SWE) 66 71 71 77
286 - Alan Dunbar 70 72 69 75, Francesco Molinari (ITA) 73 67 76 70, Daniel Gaunt (AUS) 71 68 72 75, Mikko Ilonen (FIN) 70 73 70 73, Jorge Campillo (ESP) 72 68 72
74, Graeme Storm 69 73 74 70, Peter Uihlein (USA) 67 68 74 77, Eduardo De La Riva (ESP) 73 71 74 68, Fredrik Andersson Hed (SWE) 70 71 68 77, Michael Hoey 67
76 72 71
287 - Garth Mulroy (RSA) 69 75 69 74, Alexandre Kaleka (FRA) 72 68 71 76, Anthony Snobeck (FRA) 71 71 71 74, Seve Benson 73 71 70 73, James Morrison 73 70 73 71
288 - Patrik Sjoland (SWE) 73 70 72 73, David Drysdale 72 71 72 73, Stephen Gallacher 72 70 73 73, Paul Lawrie 71 70 73 74, Andrew Dodt (AUS) 68 74 69 77, Oliver Fisher 71 70 73 74
289 - Emiliano Grillo (ARG) 73 67 74 75, Callum Macaulay 73 71 76 69, Richard Finch 71 71 78 69, Justin Walters (RSA) 72 69 70 78, Andreas Harto (DEN) 70 72 73 74
290 - Stephen Dodd 71 70 73 76, Lasse Jensen (DEN) 72 71 72 75, Sam Little 71 72 74 73
291 - Robert Jan Derksen (NED) 73 71 73 74, Carlos Del Moral (ESP) 72 72 75 72
292 - Romain Wattel (FRA) 74 70 74 74, Seamus Power 69 75 71 77
293 - Jean-Baptiste Gonnet (FRA) 67 75 75 76, Matthew Baldwin 71 73 75 74, Chris Paisley 69 72 74 78, Wen-yi Huang (CHN) 77 67 74 75
294 - Chris Lloyd 72 71 76 75
295 - Damian Mooney 74 68 76 77
297 - Maximilian Kieffer (GER) 70 73 75 79, David Howell 70 72 77 78