Around the wrist of a handshake that grips like a vice, Dónal Óg Cusack wears a band on which is stamped “ceannairceach féin smacht”, the Irish (Gaelic) for “rebel self-discipline”. As one of Ireland’s elite sportsmen, goalkeeper for the “rebel county” hurlers of Cork, he needs now, more than ever, all the control and poise that has taken him to the top. Because he has just announced in his autobiography that he is gay.

“Gay in the GAA” screamed the front-page headline of the normally staid Irish Times. GAA stands for Gaelic Athletic Association, which transcends sport to stand at the very heart of what being Irish has meant for the last century.

Archbishop Thomas Croke, the GAA’s first patron, famously wrote, in 1884, the association’s “unofficial charter” in which he abjured England’s “effeminate follies”, counting among them cricket, tennis and other “alien” sports. Even watching a game of rugby or soccer could once have landed a GAA player with a life ban.

Being gay was never part of the GAA vision — but, thanks to Cusack, 32, that will have to change now. One of the pillars of Ireland’s conservative establishment is readjusting itself to the modern world.

To understand how important this moment is for sport in Ireland and beyond its shores, consider for a moment how many openly gay men there are at the very top of their respective games. There are lesbian tennis players and golfers, but can you think of any gay men playing team sports?

Justin Fashanu tried honesty in 1990. It turned out to be a cataclysmic decision for his footballing career. His former boss Brian Clough labelled him a “bloody poof”, his brother John said he was an outcast and his career went into decline, ending in his suicide in 1998.

In 2005 the Financial Times confidently declared that “male-team sports, the last bastion of homophobia, is tottering” after predicting that three German professional footballers were about to come out. They still haven’t.

So let’s return to Cusack, from Cloyne in Co Cork — home of the greatest hurler, Christy Ring, home to Ireland’s authentic indigenous sport, the ancient, quicksilver game of hurling.

Cusack’s profile puts him on the same shelf as Roy Keane, Ipswich Town manager, former Manchester United captain and fellow Corkonian. He’s the sort of man who inspires strong feelings: a driven, sometimes tortured soul.

When we meet, in his publisher’s office, overlooking St Stephen’s Green in Dublin, Cusack is reading his e-mails with a smile. It has been a difficult few days for him as he waits to receive reaction to his autobiography, Come What May.

It’s gripping and certain to become a sports classic, because it realises the passion in a game as niche as hurling, a cultural phenomenon. The passages about his homosexuality are no more than org-anic part and parcel of the entire story, although they have, of course, commanded the biggest headlines.

“Do you mind if I read this e-mail to you?” Cusack asks, scrolling down to the right page on his laptop screen. He reads: “What Dónal Óg did took real courage. What he had to endure up to this point took even more courage. He’s an inspiration to countless people out there in the same situation, myself included.

“I sincerely hope he ignores the bigots and holds his head up high. As someone who is not out to my family yet, I can attest to the mental anguish every time you have to lie to those closest to you or change a pronoun” — and here Cusack interjects to say “this is the important bit” — “or every time a sibling introduces their girlfriend or boyfriend to the family and you would like to be able to do the same. Today Dónal Óg has one more fan. He’s given me a bit more courage on my journey to come out to my own dad.” He leans back and smiles again: “I like that. Even if that one guy did get the courage and spoke about it and went on that journey of realising that it’s not a big deal and his father went through a journey of understanding it better, that’s worth it for me.”

He says that he has always been comfortable with his sexuality, even since as a teenager he began to experiment. “I tried to go out with women to make sure, to see what kind of feeling it gave me,” he writes in the book. “I went out with nice women and good women, but sure, I still knew. I wanted something else. I get more out of men. I just do. Always have. I know I am different, but just in this way. Whatever you may feel about me or who I am, I’ve always been at peace with it.”

He claims that he is lucky to have always been surrounded by supportive friends and family, but admits that, in a world as macho as hurling, it has never been easy: “There isn’t a match goes by that someone doesn’t hurl abuse.” One of the worst incidents took place in an away match against Tipperary. During a lull, when the 53,500 capacity crowd at Semple Stadium had fallen silent, a man began chanting, from the Killinan end, through a megaphone: “He’s gay, he’s bent, his arse is up for rent, Dónal Óg, Dónal Óg.”

His mother, who attends Mass every day, doesn’t go to the matches any more. He doesn’t spare his father the embarrassment of recounting in the book his first reaction to his eldest son’s admission to him that he is gay: "We need to get you fixed.”

It was pressure from a Dublin Sunday newspaper in 2006 that made him fly home from a team holiday in South Africa to break the news to his family. In the end the newspaper never printed its story but, as Cusack says, plenty of people have known the score for a long time.

So if that was the case, why decide to come out now so publicly? “I always would have felt a duty that, before I finished my playing career, I would speak about it, because I knew it would have a bigger impact while I was still playing and potentially help guys who are maybe not able to deal with the situation as well as I think I can. I was always going to write about it; I wasn’t going to hide from it. But it’s not an all-consuming thing in my life and never has been. Hurling is seen as a macho game but I can honestly say none of my team mates have ever had an issue with it.

“I wanted to bring it across in the book that that’s just the way it is, but also with an understanding that that’s not the case with everybody. The reality is that there are some people waking up in the morning, kids around this country, and every action that they do and every word that they speak is influenced by the guilt that they feel over being gay.

“And as I would be seen as definitely not the stereotypical gay person, even if it makes it one bit easier for one of those guys or girls then I’m happy. Isn’t that a positive thing for the game and for sport?”

Cusack feels that the time is ripe for a wider debate, although he shies away from “becoming a spokesman for anybody or an ambassador for anything. I said everything in the book that needed to be said about it”.

He swerves away from answering whether he knows other sportsmen struggling with this. “It’s probably a bit like, you know I don’t think there’s any ... it’s like black footballers in the English Premier League years ago; all the abuse those boys were getting, they definitely needed to stop.

“I think it’s no different from this situation. It’s just not a healthy thing to be happening in sport, that type of abuse and stigma that’s associated with being gay.

“I’ve no doubt that, because of the type of image that’s out there, a lot of gay people who were good at sport have left the sporting world. At the very least, it’s good for the debate to happen.”

But if the debate does begin soon, he won’t be around for it. On Friday he flies off to Zambia for a month with 22 pals to build a school in a rural village. Cusack is big on perspective. He keeps a photograph of a family from the village on his work desk. “I felt guilty about taking the photo; when we first met they were picking roots out of the ground to live. You need to keep checking yourself.”

He surrounds himself with positivity. “When I wake up in the morning, the first thing I see on my wall are positive messages and images, some material things such as a house by the sea. I dream about having that. And my ideal relationship, that would be there.” Asked what that is, he laughs: “I’d say we’ll leave it at that, you’ve got far enough! But it’s no different from what everyone wants.”

Being true to himself drives him on and keeps him focused. Talking about the reasons why he chose to write about a mad night out in Ho Chi Minh City, when he woke up the next morning and didn’t know where he was, he says that it’s important for him to call things as they are. “It does give an example maybe of the challenges a gay man faces, that you’re part of a group like that, the lads are going up the town and obviously they’re looking for women and you’re looking for men. But when I came back the next day to the hotel and the lads, it was no big deal, no difference.”

Ireland has changed and is changing, but Cusack believes that even today the country’s most powerful institutions are the Catholic Church and the GAA. “The pecking order has moved around down the years, but they and the Government here are all among the most conservative institutions in the world.

“I can remember as a young lad that we would all be sitting on our knees saying decades of the rosary every night, because that’s the family I came from. Thankfully the one thing I would have always known is that I needed to think for myself. That helped me to deal with my own situation.

“If I had believed everything that was said about homosexuality by the Church over the years, I might be saying that I was going to burn in Hell for a long time. To be honest, I couldn’t find the rationale for that so it didn’t affect me.”

He looks out of the window, on the trees turning gold and russet. “Just think, only 15 years ago there were protests going on out there over the sale of condoms!”

High five: breaking sport's great taboo

“People might not respect the way you live your life, but everyone respects honesty and truth,” said Ian Roberts, the popular rugby league player who became the first openly gay Australian sportsman when he came out in 1995. He later suffered physical attacks but became a national hero and role model, campaigning against homophobia after his retirement from sport.

Known for popularising the high five, Glenn Burke was the first Major League baseball player to come out during his career. In 1979, the Los Angeles Dodgers traded Burke to the Oakland Athletics, a move that he later said was due to his team-mates and managers knowing he was gay. He quit baseball a year later and by the 1990s was living on the streets in San Francisco. In 1995 he died of Aids complications.

In 1990, the former Nottingham Forest and Norwich City player Justin Fashanu revealed that he was gay in the News of the World. His career nosedived after rumours about his sexuality circulated at Forest in the early 1980s; this has since been blamed on the hostile treatment that he received there.“I confronted him about his sexuality publicly,” his manager, Brian Clough, wrote in his autobiography. “I did it in front of the other players and in front of almost anybody I talked to. I was extremely unkind to him.” In 1998 Fashanu’s body was found hanged in a garage in East London; he had been accused of sexually assaulting a teenager in the United States. A campaign has been founded in his name to promote the inclusion of openly gay players in football.

One of the fastest men in the world over 800 metres, Derrick Peterson told a gay magazine in 2002: “I don’t really care what people think of my sexual orientation. I like men and women. I’m definitely not heterosexual.” He was praised as the first openly gay or bisexual African- American active sportsman. But later Peterson said he had been going through a phase when he gave the interview, was not gay and had a girlfriend.

In 2007, John Amaechi, the basketball player, caused a sensation when he announced that he was gay, the first NBA player to do so. One co-player said he would want a gay player removed from his team while others praised Amaechi’s courage. Some campaigners were disappointed that Amaechi had waited until retirement. “Pro sports are a business,” said Amaechi at the time. “All the things that I have experienced in the last week would have been multiplied many times had I still been playing in the NBA.”

Chloe Lambert