Home players Simon Thornton, Neil O'Briain, Colm Moriarty and Cian McNamara secured Irish Open spots in the 36-hole qualifier at Rosapenna.
Thornton added a 71 on Sunday to his opening 68 to finish on five under before beating O'Briain (72) in a play-off to pick the £5,300 first prize.
Moriarty booked his Ballyliffin spot as a 73 left him on four under.
McNamara earned the final qualifying berth after beating Kevin Phelan in a play-off after both finished two under.
Thornton, who is touring professional at Wicklow golf club Tulfarris, spent a number of years on the European Tour and won the St Omer Open in 2013.
The scorching weather that had marked out the practice day and the opening round on Saturday was replaced on Sunday by cloudy skies and a stronger breeze that tested the players.
"It was a battle but I'm used to that from practicing at Newcastle," said Thornton.
"Overall, I played two good rounds. I played lovely, only one sloppy shot which cost me a bogey on the last but I committed to everything. I'm delighted obviously."
The Irish Open will begin at Ballyliffin on Thursday with BBC Sport Northern Ireland providing extensive coverage on TV, radio and online.