The Spaniard entered the final day at Lahinch Golf Club five shots off the lead but made eight birdies and an eagle to get to 16 under and win this event for the second time.
Wiesberger and Rock earned places in the field at The Open Championship with their top ten performances, as did England’s Paul Waring, who finished at 12 under along with another Spaniard in Jorge Campillo.
It was two years ago that Rahm lifted this trophy in his rookie season for a maiden European Tour win and he now has four to his name – with three of those coming in the prestigious Rolex Series – in just his 34th appearance.
The victory moves the 24-year-old to the top of the Race to Dubai Rankings Presented by Rolex and also takes him back into the top ten on the Official World Golf Ranking.
Rahm made no secret of his affinity for Ireland in the build up to this week’s event and he has now continued that love affair with a weekend of 64-62 to make it at least two worldwide wins in every full season since he turned professional in 2016.
“I love this tournament,” he said. “I love this country. I love the people and feel like I’m at home every time I come.
“I’m excited to repeat. I think Seve was the only Spanish player to win more than one and to join my name to that Cup again, it’s special. It’s probably one of my favourite trophies that I have at home and to have another one, it’s definitely a special moment.
“The list of winners, Faldo, McIlroy, Olazábal, Seve, the champions at this event, and to put my name on there is really special.
“My game was in great form, it just didn’t show the first two days. I couldn’t hole the putts and the weekend was the complete opposite.
“I knew I had to do it today to have a chance and, man, I kept looking at the leaderboard and looking up and after ten, I’m like, ‘okay, let’s get a good run’ and that eagle on 12 just completely got me going.”
Rock started the day with a one shot lead but he dropped a shot on the third and after five holes playing partner Cabrera Bello led by three thanks to a long left to righter on the first, a ten footer on the fourth and a tee shot to tap-in range on the fifth.
A Rock birdie at the seventh from eight feet kept him in touch but it was Rahm who was making a charge through the field.
After holing a long putt from off the green at the second, he gave the shot straight back at the next but sandwiched an approach to three feet on the seventh with birdies from just over six feet on the fifth and ninth to turn in 31.
A 15 footer on the tenth edged Rahm further up the leaderboard and when he holed a monster after getting on the par five 12th green in two, he soon found himself in a share of the lead.
A poor chip on the 13th saw Rahm surrender a shot but Cabrera Bello failed to get up and down on the tenth and chipped into a bunker on the next to make it a three way tie.
Rahm put his approach to eight feet to edge ahead on the 14th but Cabrera Bello hit back with a wonderful up-and-down from the sand on the 12th before bogeying the 13th and 15th to fall back.
A sensational gouge out of the rough on the 15th to three feet moved Rahm to 15 under and while Rock birdied the driveable 13th, he bogeyed the 15th, allowing Rahm to put the icing on the cake with a birdie from ten feet at the penultimate hole.
Sullivan and Wiesberger both carded six birdies and two bogeys in rounds of 66 but never truly challenged as birdies on the last moved them into second.
Pepperell made a third birdie of the day on the last to sign for a 69, while Cabrera Bello also took advantage of the par five in registering the same score.
Campillo and Waring both signed for rounds of 66 to sit a shot ahead of Gavin Green, Martin Kaymer, Zander Lombard, Mike Lorenzo-Vera and Edoardo Molinari.