No Irishman has won this title since John O'Leary in 1982.
"This is the first time I have been here," said O'Hern, who has four top-10 finishes in his last five starts. "The course is fantastic. I love links golf where you have to think your way round and shape your shots.
"I was pretty annoyed I didn't get in the British Open last week at Royal Troon. I think that place would have suited me down to the ground. But I love this course."