We sit in the cramped corner of a small Dublin coffee shop. But somehow, it feels like we really should be sipping afternoon tea from china cups in a chintzy, period drawing room. Because there is something old worldly about writer Robert O'Byrne, from his impeccably good manners right down to the silk hankie in his jacket pocket and those trademark horn-rimmed spectacles. "Now what do you know about me?" he asks briskly. "Very little? Really? That's awfully good news. Therefore I should keep it that way." This challenge is delivered in BBC wireless accent, circa 1930s. Posh, in other words (a description he'd surely find lazy). And unfortunately, this writer mis-hears slightly when he replies to a enquiry about speaking confidently on the radio. "I'm fun on the radio? Oh yes, I'm really a deeply fun person..." he adds with a grimace. "No, I said I'm fine on the radio."

On the page, this could make Robert O'Byrne sound pompous and disagreeable. In person, he's anything but, and instead, is warm, gracious, and with good humour to match the good manners. So much so that it feels like very bad manners on the Tribune's part to persist in asking him about his private life. Given that he writes about art, architecture and those notable Anglo Irish figures from the recent past who are invariably described as gentlemen (his latest book, for example, is Desmond Leslie, the Biography of an Irish Gentleman) can we assume his life is lived in a constant social whirl? (The previous night he'd spent in the RHA launching the book with lords and ladies in attendance; after our interview, he's off up to Castle Leslie for its second launch hosted by Sammy and Jack Leslie.) But no, it's not all champagne and soirees.

"I don't mix with those worlds by and large. I know quite a number of artists, for example, but my social life is not based around the art world. Likewise, I know a lot of writers, but wouldn't be a part of that literary world. I'm probably not part of any world. Happily so... I'm dying to see your questions..." he breaks off, and snatches my hastily scrawled notes for a quick, uninvited scan. Being interviewed about himself is something he finds slightly amusing, but he also doesn't want to come across as sounding smug or boring. "No, you don't really want me to rattle off my CV? That would be very tedious from your point of view, surely?" But having worked in journalism for over 20 years, he accepts that readers are curious about the private, as well as the public, lives of interviewees. And there are some details which come as a surprise. For a start, Robert O'Byrne is in his 50s.

"No, stop with the flattery, I really was born in the l950s. In London, but I grew up in the Middle East as my father worked in the oil business there. The greater part of my schooling was in England. But then, I didn't want to be in school in England anymore." By that stage, his parents had bought a house in Dublin and O'Byrne came here and completed his final two years of secondary education at Gonzaga. What did he make of the Jesuits? Did they stand up to their reputation for intellectual rigour?

"No, I thought they were disappointing when I was there. I had read a great deal about them beforehand. They failed to live up to my high expectations. But it was an entertaining enough time." Next came Trinity, where he studied for a degree in history, and also completed a diploma in the history of European painting. Then another surprise – after college he considered taking up the religious life and went to train at Glenstal Abbey. He changed his mind and left after 18 months, although a serious approach to religion wasn't just a phase, he stresses.

"Religion has always been very important to me. It's still important. I was raised a Catholic, but attend services in the Church of Ireland on now. I prefer the Church of Ireland." That's because he has struggled with doctrinal difficulties regarding the Catholic Church, such as tran­substantiation, papal infallibility and devotion to the Virgin Mary. The Anglican communion is easier, more democratic in its structure and management, he says. After Glenstal, O'Byrne did a course in arts administration, then worked for a time as a museum curator in Roscrea, and from there moved on to Limerick as a regional arts officer.

After moving to Dublin, he set up the Music Network and by the late l980s was organising events at the then newly opened Irish Museum of Modern Art. Then came a career in full-time writing with The Irish Times in the early 1990s. He was a regular at fashion shows and launches back then, conspicuous in being practically the only male among the throng of female fashion writers, but nonetheless looked so organised and confident. "Well, you go in, you talk to people, then you leave again. But I was so glad when I stopped doing fashion."

There was no degree of re-invention necessary when he shifted the focus to writing on the arts and architectural heritage, he says, nor did he experience any raised eyebrows or snobbery on his becoming an expert in a different field. All of these creative disciplines are related, although he questions whether fashion remains a creative force before setting off on a lengthy explanation of that view and finally concluding with "that's all very meandering and I don't expect you to use any of that in your piece".

He remained with The Irish Times until 2002, but "took the pay-off" when the newspaper instigated cuts due to over-staffing. Although it meant leaving the relative security net of a contract, he has never been an organisation person, a nine to fiver, or "a team player". He's tried his hand at fiction, but discovered it was incredibly difficult – "and there are enough bad novelists around". An obvious question: does he make enough from freelancing and books to survive these days?

"Well, you don't do writing to become rich. I don't write to make money, although, thank goodness, I make enough – but only enough, I might add."

Witty and engaging though he is, O'Byrne comes across as very grounded underneath it all. He doesn't do self-deprecation – "that's something you leave to others," he advises. But as a writer, he's required to put himself out there and invariably risk criticism. His recently published Dictionary of Living Irish Artists has had some mixed reviews from newspaper art critics. Does he always read reviews?

"Of course. I try to see what is useful, to learn from it. One should always be trying to improve oneself in every way one can. So it's very important that one should take all criticism seriously. It would be lazy to dismiss criticism as begrudgery."

He lives "in the middle of the Irish countryside", likes his close circle of friends with whom he never has discussions about who's just been kicked off The X Factor or The Apprentice. That's because O'Byrne doesn't have a television. He had one 10 years ago, it broke, and he's never got around to replacing it. But the radio, now there's something he can talk about. And Joe Duffy. He tunes in faithfully every day.

"No, I swear, cross heart, hope to die. His programme is utterly fascinating. I lead a quite secluded life and it's a very good way of keeping me in touch with the broader base of Irish society. I can see why a lot of people use Joe Duffy as their first port of call, to complain about an injustice or to start a campaign." Because politicians are so preoccupied with economics, Duffy is "tremendously important" in allowing people give expression to their opinions, says O'Byrne. "It's the one place where people can be guaranteed a sympathetic ear – although not an uncritical one. Joe Duffy is very astute. He's not a rabble rouser – which is one of the mis-apprehensions about him. Although over the past year, you have so many people ringing him to say we need a revolution."

But revolution is unlikely to happen as Irish people generally are more conservative now, says the man who took part in the Wood Quay and PAYE protest marches of the late l970s.

A couple of years ago, O'Byrne wrote an opinion piece for The Dubliner magazine in defence of the middle class. Trevor White, editor of The Dubliner, commissioned the piece because, O'Byrne recalls, "he was very keen to stir up controversy in order to stir up sales". But he misjudged the Irish psyche. "Realis­tically, it's been half a century since Irish people have been stirred up by something in print – ­tell me something that has appeared in print that causes people to ring Joe Duffy?"

As for being middle class, Irish people have a very conflicted attitude. Some are "afflicted with the Bertie Ahern syndrome of saying they are proud to be working class", he says, while it remains a discomfort for many to be called middle class with all that that implies. In England, it's regarded a compliment; in Ireland, it's a slur, and he quotes a voice from the past to demonstrate that comparison.

"Sean Ó Faoláin, back in the l940s, said Ireland was 'a nation of urbanised peasants' with people making much of their pride of being part of rural Ireland, proving that they were more grounded, decent and honest. By and large, there is no greater insult you can throw out than to classify someone as being Dublin 4. But it's only a postal district after all."

Similarly, the reason the nation's interest in Ireland's architectural heritage appears in marked contrast to that of our nearest neighbours is down to our history of colonisation. As a board member of the Irish Georgian Society (and author of a celebratory 2008 book on the same subject), O'Byrne is keen to promote a greater appreciation for the grand houses and estates which still survive. "These period houses are great examples of Irish workmanship. It was Irish skills that designed, built, decorated and furnished these homes and that should be celebrated."

The Irish Georgian Society gets huge support in America, but still doesn't enjoy that level of enthusiasm here, he explains. There is ambivalence to donating funds to keep historic buildings standing. But we should take responsibility for our heritage, he stresses. "We shouldn't be selective about our history, but appreciate that it's much more diverse. There is also an obligation that when we are gone, the next generation can enjoy it."

Already working on his next two books, he's also heading off to the States for what will be his third trip this year on behalf of the Irish Georgian Society. He likes his work, and suggests that if you want to really find out what makes him tick, take a look at his writing.

"I think people get a very good sense of what a writer is like over time, even when the work is factually based. You should always read between the lines." He will keep listening to Joe Duffy for updates on the state of the nation, but is very aware that "one could get hooked on a misery diet if one wasn't careful". Time spent in the company of gentleman Robert O'Byrne is surely as far from a misery diet as you could get.

'Desmond Leslie: The Biography of an Irish Gentleman' (Lilliput Press); 'Dictionary of Living Irish Artists' (Plurabelle Press)