Shane Lowry won the Irish Open as an amateur in 2009. Royal County Down and Royal Portrush have each hosted it four times.
Ballesteros endeared himself to Irish fans by winning the Irish Open in 1983, 1985 and 1986.
But perhaps the Spanish victor Rahm bears closest comparison with is Masters champion Sergio Garcia who clinched the title aged just 19 at Druids Glen.
Rahm's highlights from Sunday include an eagle on the fourth hole from 150 yards out.
From then on he looked in cruise control, rounding out his front nine with three consecutive birdies and adding another at the tenth to reach 23 under. "To keep up with the leaders I have to play explosive golf on the last day", he said. His four-round stroke total of 264 was also a tournament record.
Rory McIlroy's British Open preparations were in disarray Friday after the former world number one missed the cut at the Irish Open for the fourth time in five years. Fleetwood has earned more world ranking points in 2017 than any player except Dustin Johnson.
Rank outsiders Im and Hebert both shot rounds of 67 to lie 13 under and retain the one-shot lead they held over the chasing pack after the first round.
Richie Ramsay of Scotland also closed with a 65 to climb the board and end the week in a tie for second place with England's Matthew Southgate.
The errant ball-placement-a matter of millimeters-was discussed between Rahm, Im, and European Tour chief referee Andy McPhee, and ultimately Rahm was not penalized.
There's no doubting that the sweeping Pat Ruddy-designed Glashedy course will make a magnificent venue.
Ultimately, it was all about Rahm, who produced spectacular scoring golf on the final day to continue the 22-year-old's rise as one of the sport's burgeoning talents.