The 27-year-old Irish born flanker emigrated to Australia with his Irish father, Australian mother and older brother Mark in 1983. Keith made his Irish international debut against Wales in the 2002 Six Nations and since then has been a regular on Eddie O'Sullivan's side.
A star under-age player, Gleeson was a regular Australian U21 and a Waratah.But a combination of bad luck and falling out of favour with the Waratah management three years ago saw his chances of pursuing a professional career in Australia diminish rapidly.
Speaking to the Irish Echo in an interview last year, Keith said he had always wanted to be a Wallaby, but jumped at the chance to play for Ireland when it came.
"I've always considered myself an Australian but Irish born.Wearing the green wasn't what I dreamed about when I was young, it wasn't what I was aiming for. But I still feel very proud to represent Ireland, it's a great honour to wear the Irish jersey."
He joined the Waratahs as a professional player in 1998, aged 22 and played on a NSW team that beat Ireland in Sydney in 1999. The Irish management approached him then to declare for Ireland but he turned down the offer.
Within two year everything had changed when he was left out of the Waratah's team. But when Matt Williams was appointed Leinster coach and asked Keith to join he jumped at the opportunity.
"I'd come through the Australian under-21s and to a certainextent could not see myself not playing for Australia, but I guess life doesn't always week out like you planned it. I guess it just came down to coach's preferences the way these things sometimes do. I still believe I'm good enough and Ibelieve I'm better but it's a case of being picked and being able to prove it," he said.
Speaking about Ireland's chances in Rugby World Cup, Gleeson was optimistic. "Our big game in the World Cup is going to be Argentina in Adelaide, that's no secret. It's definitely the game we want to win, if we take Australia's scalp, well that's just a bonus."
Speaking to Irish Echo reporter Tom Felle from the Irish squad's camp in Terrigal yesterday,he said he never thought after the 1999 world cup that he would be playing for Ireland in 2003.
"Four of five years ago I was still playing in Australia, in 2001 anopportunity presented itself to go back to Dublin and here Iam," he said.
Gleeson said that playing in a world cup in Australia was an addition for him.
"Australia is certainly a comfortable environment to play in," he says, although he adds his time with Leinster is also proving very enjoyable.
"Over the last who years living in Ireland has really broughtback by Irishness to a certain extent. "It was always a part of me, initially when I moved over I had an Irishaccent, something you try and lose as quickly as possible,particularly when you're a young kid trying to fit in. Then it was partly ironic that when I moved back to Ireland I had an Australian accent. I don't fit in again!"
Coming back to play in Australia, he says he has a point to prove. "There'salways something you want to prove to yourself every time you play against the top players in the world. Unfortunately at the time I came thought as a forward in new south Wales, I was probably four or five years younger than anyone else on the team. It was very hard to break into and then havingthree different coaches in four years certainly didn't help things.
"The opportunities sometimes don't go your way, but it's turned out for the best. There is always something extra special when I play Australia. I want to beseen as probably better than what is here, I wouldn't be human if I didn't say so."
Gleeson says the squad are prepared, mentally and physically for the Romanian game on Saturday. In many ways, it's a dream start for Ireland, butas Gleeson cautions, in the past Ireland took Romania for granted, something that wouldn't happen again.
"We've spent the last couple of weeks going through the otherteams, and in the last couple of days we've been focusing on Romania. Certainly this week we've been mentally building up and stepping it up in training. There are obviously a lot of guys who were fighting for places. Tuesday morning'sbreakfast was the quietest we've had. Teams are always announced on Tuesdays and not much gets said before hand."We got a rude awakening against Romania last year. I think we saw them as a second rate rugby nation but at the end of the game we said hang fellas we didn't exactly perform too well there. They came out a very physical sideand although we won comfortably in the end they made life very difficult for us for 70 minutes.
"It's probably not a bad game to go into because we are prepared physically for the game and that's what the world cup is about because if we had an easy team up first then we're not really going to get up for it. Some of us haven't played a game in four or five weeks so we do really need a hard game up front to get back into the swing of things."