CORK, June 22, 2014 (AFP) - Despite an anxious last hole bogey, the 34-year-old shot a final round 70 on Sunday to win by a shot with a 13-under par tally on the sun-splashed Fota Island course.
The win is Ilonen's fourth Tour title while his 333,330-euro first prize cheque has sent him through the five-million-euro barrier in Tour earnings.
And victory ensures Ilonen becomes the first-ever Finnish-born player to break into the top-50 on the world rankings.
"Well, it's a very humbling moment to look at these great names on the trophy as there has been good winners of this tournament so it's a big thing for me," he said.
"And to get myself into the top-50 on the rankings was a goal of mine that I set up myself to achieve three years ago when I was off for six or eight months because of my ankle surgery.
"I'm on the third of that plan so it's gone according to the plan but I need to win at least one more to get to my bigger goals."
Ilonen revealed encouraging him all week was Kaymer, a recent wire-to-wire U.S. Open winner.
"Martin and I are good friends and he has been texting me all week encouraging me on to win this week," he said.
"And for me to win wire-to-wire, it was very much Martin Kaymer-inspired win.
"I sent a message to him last week that I really enjoyed watching golf. I very rarely enjoy watching golf; I would rather play golf, but Martin's win inspired me. It was nice to keep that lead all the way.
"I am playing in Cologne next week so I am looking forward to catching-up with him."
Italy's Edoardo Molinari shot a four under par 67 to be second on 12-under par with three players, the England pair of Danny Willett (71), Matthew Baldwin (69) and Swede Krisoffer Broberg (69) sharing third on 11-under par.
Molinari along with Willett and Baldwin secured the three spots available into next month's British Open at Royal Liverpool.
Crowd favourite Graeme McDowell was never in the hunt for his first Irish Open success signing for 71 to finish three shots behind the Finn in a share of sixth place.
And England's Matthew Fitzpatrick celebrated his first event as a professional earning 17,500 euro for his share of 29th place.
Leading scores after the fourth and final round of the Irish Open at the par-71 Fota Island course on Sunday (GBR & IRL unless stated, par 71):
271 - Mikko Ilonen (FIN) 64-68-69-70
272 - Edoardo Molinari (ITA) 67-69-69-71
273 - Krisoffer Broberg (SWE) 69-69-66-69, Matthew Baldwin (ENG) 67-71-66-69, Danny Willett (ENG) 73-66-63-71
274 - Magnus A Carlsson (SWE) 66-71-68-69
275 - Graeme McDowell (NIR) 68-66-69-71, Ross Fisher (ENG) 68-72-70-65, Chris Wood (ENG) 69-69-70-67, Michael Hoey (NIR) 68-71-70-66, Richard Finch (ENG) 68-72-67-68, Gary Stal (FRA) 70-67-69-69, Gregory Bourdy (FRA) 68-71-67-69
276 - Marcel Siem (GER) 66-74-71-65, Matthew Nixon (ENG) 70-65-74-67, Padraig Harrington (IRL) 69-67-71-69, Adam Gee (ENG) 68-70-69-69, Gareth Maybin (NIR) 71-65-69-71, Simon Khan (ENG) 71-65-69-71, Fabrizio Zanotti (PAR) 70-69-65-72