The 67-year-old Galway man was best remembered for helping Europe win the Ryder Cup at The Belfry in 1989 when he fired a stunning shot with his two iron to within a few feet of the 18th hole.
President Michael D Higgins and Taoiseach Enda Kenny led a flood of tributes to the sporting icon.
“I knew Christy personally and he loved and lived life to the full. His premature passing will be a source of great sadness to many Irish people and all golfing fans in Ireland and across Europe,” said Kenny.
President Higgins said: “As a sportsman, and as an iconic figure in golf, Christy represented his country and its people on the international stage with distinction, dignity, and great humour.”
O’Connor Jnr, who is survived by his wife Ann, son Nigel, and daughter Ann, had been on holiday in Tenerife when he died in his sleep. The golfer’s other son, Darren, died in a road accident in 1998, aged 17.
The Golfing Union of Ireland paid tribute by posting a clip of the memorable shot online and a note describing him as “a gentleman, an iconic figure of Irish golf, and a true ambassador”.
“He was a pioneer for professional Irish golfers and inspired a generation of players,” the organisation said.
O’Connor Jnr’s famous 220-yard shot on to the 18th green to win at The Belfry is an image that has pride of place in the minds of all Irish golf and sport fans.
Up against the world number one at the time, Fred Couples, and the oldest man in Team Europe, O’Connor Jnr had been written off by large sections of the media before he took to the course that day.
Among his other wins were the Irish Open in 1975 and the Dunhill British Masters in 1992.
Elsewhere, after joining the over-50s ranks, O’Connor Jnr won by three-shots in the 1999 Senior Open Championship at Royal Portrush, before returning to the North a year later to successfully defend the title at Royal County Down.
He also lifted two titles on the Champions Tour in America in 1999.
Among his famous course designs are Shane Lowry’s home course Esker Hills, Co Offaly. The world No 21 described Junior as an “absolute legend of Irish golf”.
Former Ryder Cup captain Paul McGinley said: “This is a terribly sad day for Christy’s family, obviously, but also for all of Ireland and lovers of golf worldwide.”
McGinley enjoyed dinner in Dublin with O’Connor Jnr, along with some other big names from Irish golf, just before Christmas.
“We had a great night, full of memories, full of stories and full of good old Irish craic and laughs, and it is the laughter and fun that I will remember most about Christy,” he said.
Tony Jacklin, the former Ryder Cup captain, who picked O’Connor Jnr as a wildcard in 1989 after controversially leaving him out in 1985, recalled the magical finish to retain the trophy.
“Looking back, it was very hard not to pick Christy for the 1985 Ryder Cup team but Jose Rivero had won on The Belfry that year so it was obviously a decision based purely on golf. But we were delighted to have him on the team in 1989 and I remember he was very excited when I told him,” said Jacklin.
“Christy hit a wonderful tee shot and then Fred pulled his, but because he was so long he cleared the water, leaving himself with a nine iron, while Christy had a two iron. I said to Christy, ‘Come on, one more good swing for Ireland’, and of course he hit the shot of his lifetime. We couldn’t have retained it without him. He had a great effect on the team room too. We had a great team unity and he was a big part of that.”
Wicklow man Eamonn Darcy is another Irish Ryder Cup hero and was one of Christy’s closest friends.
“He was larger than life and a great lost to our country. When he came into a room everybody knew he was there. He was just a good guy. He was just a great family guy and he was an incredible golfer. As for the 1989 Ryder Cup shot, he’d been left out a couple of times in Ryder Cups before that and it was just marvellous that he had the chance to show just how good he was under pressure. And he was. I mean, right through his life under pressure, he was just so good.”
Ken Schofield, European Tour executive director from 1975-2004, said: “Much more so for everyone involved with the tour and the game of golf, Christy will be remembered as a gentleman spirit — every amateur golfer’s dream as the perfect pro-am partner, on and off the golf course.”
Former mayor of Galway John Mulholland was a great friend of O’Connor. He said: “He would never insult anybody or speak ill of anybody. He was a gem. He was one of those gregarious people, a delight to meet at any time. Any where he brought you or you brought him, he was the star attraction.”