“Gee whizz,” declares Pádraig Harrington when he is informed of his latest slice of history.

By teeing it up at Doonbeg on Thursday, Harrington will feature in the Irish Open for a 31st-straight year. It will extend his record streak at the event – Eamonn Darcy is next on the list with 28 appearances – and put Harrington ahead in terms of consecutive appearances at any national open. The record was previously held by Seve Ballesteros, who didn’t miss a Spanish Open appearance for 30 years.

“And I still think I can win it,” he adds, with a self-deprecatory laugh.

Harrington’s longevity flows from his magnificent, incorruptible enthusiasm. He is, after all, a 55-year-old man still using phrases like “gee whizz”. He is also the only likely candidate among this week’s field to complete a 23-minute press conference and express disappointment that it had ended so soon.

“I am a golfing nerd,” he says. “I’m very happy, at 55 years of age, to realise that I am, and I do accept it. I do absolutely accept the fact that I love this game.”

He talks through his many enthusiasms, which have lately included spending five hours to shoot a video with the DP World Tour, in which he was given 500 attempts to make a hole-in-one at the K Club. He pauses to issue a spoiler alert before earnestly lamenting his failure. “I cannot believe I did not have a hole-in-one,” he says. “I was so cocky, ‘I’m going to do this.’ I picked the pin position, 137 yards. [The disappointment is] so bad I actually want to go and do it again.”

Harrington says the length of his career is not very different from his peers, tallying it at 20 years and splitting it into three acts. First was an eight-to-10-year peak, followed by 15 years of burnout and a closing five years “on a slippery slope”. Though he has continued to win with regularity on the Champions’ Tour, Harrington describes the 2015 Honda Classic and 2016 Portugal Masters as his twilight triumphs. “But the game was really hard for me, I was trying so hard,” he says. “I was going out there shooting 72, 73 and coming in sitting with young lads at lunch and wondering, ‘Should I be there?’ I was very much burnt out.”

This lengthy epilogue owes much to fostering that enthusiasm for golf and the peripatetic life it demands. He says he is now more relaxed and he will adjust his schedule to fit around dinner invites. “I still practice, and I certainly still need to go to the gym, I still need to do physio. But my number one priority at tournaments is to enjoy myself.”

He has learned to enjoy the Irish Open, too. He calls it his fifth major and says the adulation of the home crowd bred pressure in his own head to perform.

“It takes a while to figure out that everybody wanting you to do well is not them expecting you to do well,” says Harrington, “and once you get a handle on the fact that it’s just a genuine hope that you do well [it’s less pressure]. It always felt like you were letting them down back in the day if you didn’t hit a perfect shot.”

He learned to handle the pressure and his sole victory in the event, at Adare Manor in 2007, prefaced his glorious major run. He won the Open Championship at Carnoustie two months after winning in Limerick and added another two major titles the following year. “Winning in 2007 was a big step in how to manage a big tournament week and how to handle the pressure from Monday morning onwards,” he says.

Doonbeg will be the 18th venue at which Harrington has played an Irish Open, though he has some experience of these links having played an exhibition match with course designer Greg Norman to mark its official opening in 2002. Norman won by a single hole. Asked about his memories of the day, Harrington first spoke about Norman and a late flare of his competitive spirit.

“Greg had kind of finished his career at that stage, and I was coming in thinking I was going to have a pretty soft match and I couldn’t believe how into it and competitive he was,” says Harrington. “It was nice to see him really into his golf. All guys want to see their predecessors, the greats, they want to see them at their prime. They want to see them at their best, and certainly on that day, I got to see Greg Norman at his absolute best.”

It is instructive that Harrington’s abiding memory of a day almost a quarter-century ago is the enthusiasm of his opponent.