The 30-year-old closed with a 4-under 67 at Portstewart Golf Club to finish at 17 under and in a share of fourth to earn one of the four Open Championship spots up for grabs.
Fox also narrowly missed out on qualifying for the Open at last year's Australian Open because of his world ranking position when he finished in a share of 4th behind the winner, Jordan Spieth.
"I’m ecstatic,” said Fox. “Third time lucky, I just missed out last week in France, and I missed out on world rankings at the Australian Open at the start of The Open Qualifying Series so I’m very, very happy to get the job done this week.
“It was a great golf course this week and a lot of fun to play. I’m sure Birkdale might play a bit tougher than what we’ve got this week. I haven’t played a lot of links golf in my career, I managed to play an Open at St Andrews a couple of years ago and I loved the experience of playing links golf. I’m looking forward to the opportunity again.”
Fox finished seven shots behind runaway Irish Open winner, Jon Rahm of Spain.
Joint runners-up, Richie Ramsey and William Southgate, also gained Open starts and with fellow 4th place-getter Justin Rose already exempt, Fox and David Drysdale earned the final two places as they had a higher world ranking than Daniel Im who was also tied with them.
The cheque for €240,000 surpasses that Fox earned last week in Paris as the largest he has received as a professional and he has now earned over €450,000 in his past two starts moving him to 28th position in the Race to Dubai with over €600,000 for the season.
22-year-old Rahm closed with his second 65 of the week to win by six shots and is likely to move to 8th in the world rankings when the revised rankings are finalised.
Rahm poses with the trophy after his impressive victory.
It was Rahm's first win in Europe having already won on the PGA Tour and he was moved by the achievement.
“It's really hard to explain right now,” said the champion. "I know the trophy is right next to me and my name is going to be there for ever now, but it seems hard to believe that it's happened.
“It's somewhat surreal. It's hard to explain. I just look at it and I see Nick Faldo, I see José Maria Olazábal, I see Nick Faldo again, I see Colin Montgomerie, Ian Woosnam, Seve. That's a list of the greatest European Tour players ever, and to have my name next to it, and the last one - Rory McIlroy – it's so special.
“Not just to win this event but to win it at the place I just won it, Portstewart – a great golf course – and with the fans supporting me better than I've ever seen anybody support me. It's been unbelievable.
“I've never played my best golf. To actually play my best golf that I can remember till this day and shoot 24-under on this golf course and win it by six - that is not something I would have believed I was capable of. I learned a lot about myself and what I'm capable of, and it's a really, really special day.”
Rahm moved to 3rd in the Race to Dubai money list.
Wade Ormsby continued his improvement to finish 14th, Andrew Dodt and Scott Hend were 20th, Marcus Fraser 36th and Sam Brazel 62nd.
JON RAHM: PLAYER PROFILE