"There is lovely Chinese proverb that goes: 'Don't open a shop unless you like to smile'", says Feargal Quinn. Quinn likes to smile. He has also opened a lot of shops. As the founder of the supermarket chain Superquinn, the 73-year-old was at one time the most famous, and richest, shopkeeper in Ireland, before the family sold the business in 2005 for a sum reported to be in excess of €400 million. Now the businessman and independent senator is about to become a reality TV star with Feargal Quinn's Retail Therapy. This six-part series, in which he uses his expertise and charm to rescue ailing retail businesses from the brink, is all about back to basics. "I am first and last a shopkeeper", he says. And smiles.

Like the man himself, it's a can-do type of show. He strides down main streets like a latter-day gunslinger (with a colourful tie) as he sets about transforming a jaded business into one with a potentially bright future. First stop is X-it department store in Finglas and thereafter it's off across the country, from a department store in Claremorris to a florist's back in Dublin's Coombe. At all stops, Quinn is at the coalface; cajoling sometimes reluctant businesspeople to change their ways.

Dressed in a pinstripe suit, with a trademark rainbow-coloured tie and his Papal Knighthood pin on one lapel, he is getting ready for a session in the Seanad when we meet. An early riser, he spent part of the morning on a review of a new biography of British Petroleum boss, Lord John Brown. "Sir John", he says, "was all about profit."

After half an hour in his company, you feel you've known him all your life. By the time you're saying goodbye you believe you've made a new best friend. Quinn has that magic. Most of his answers wander off into anecdote ("this is a lovely story") whether it is how he met his wife, Denise, or how Superquinn stood out from the very beginning (one in-store competition offered the grand prize of a three-minute phone call to America). Such repartee comes naturally - he's been telling stories ever since he worked as a bingo caller at his father's holiday camp.

But beneath the bonhomie is the businessman. At its height, the Superquinn chain had 21 stores with a total staff of over 5,000. On the world stage it was listed at about 290th but in sales per square foot of selling space it was ranked 20th, a measure of its innovative and 'consumer as king' philosophy. Quinn was lauded as a retail guru, especially in the wake of his 1990 bestseller, Crowning the Customer. In 2005, when the family sold the chain to Select Retail Holdings Group (for "a reasonable amount" as he puts it), the main reason quoted was that Superquinn was being frequently outbid for potential sites by larger groups. But again Quinn was ahead of the curve: making a tidy sum just before the Celtic Tiger lost its footing.

Since then, Quinn has invested his energies elsewhere. He is on a number of boards, including the US Food Marketing Institute and in 2006, he was appointed Adjunct Professor in Marketing at NUI Galway. He is also the former president of the EU-wide lobbying group, Eurocommerce. "I had to negotiate with my wife, Denise, to accept that position because she said that she'd never see me", he says with a laugh. And then there's the Seanad, where he has worked since 1993.

From the very beginning, Quinn always wanted to be his own boss. "I think that comes from being in a business family", he says. "And it's a compliment to your parents if you follow what they do." Born in Dublin, Feargal went to boarding school at Newbridge College. "I know that some people found boarding school very lonely but I suddenly found myself with lots of 'brothers' and really enjoyed that", he says.
When he was ten years old, Quinn's father, Eamonn, opened a holiday camp at Red Island in Skerries in Dublin. Young Feargal worked as a shoeshine boy, a newspaper seller, a bingo caller and a photographer. "I would have thought that I was very shy as a teenager but I think that it gets knocked out of you in a holiday camp."

He was also learning the basics of business. An early, vivid memory of his father is of both of them listening to AFN (America Forces Network) on the wireless in the mid-'40s. The network's doctor suggested that as people were not getting enough exercise they should always run upstairs. "My father always ran up the stairs after that as I do to this day", says Quinn. "My father brought fun into life. My mother was much more traditional, more religious and more concerned about your behaviour. There was no question of bad language or anything like that. She was very strict in that area.

"I found my father's death very difficult," he says. "He died on the way to the funeral of a family friend, who was killed in a plane crash in England in 1972. That was a disastrous year because later that year my brother-in-law was shot dead up north. Up to that point I had no experience of death and suddenly they all came together. My mother died some seven years later. She had been ill for a while so it was not quite so difficult as the sudden death of my father."

He met his future wife, Denise when he was 21. "She was 16 and her father was an army officer in Athlone and had retired. They have five children: Eamonn, Gillian, Stephen, Zoe and Donal. "Zoe was called Zoe because it was the last letter of the alphabet and Denise figured that she would be the last child", says Quinn. "Then Donal turned up two years later." All were sent to France for their education because, as Quinn puts it, "if you learn a language before you're fourteen you will speak it without an accent". Today, two of his daughters are married to Frenchmen and he has twelve grandchildren.

Any regrets that he might have spent too much time on business matters and not enough with his young family? "I would argue that that did not happen but you would have to get Denise's view for the full picture", he says. "I believe I did reasonably well. For example, we live in Howth and growing up the children had their horses. So after a very early start in the morning, I would come home at lunchtime and spend time with the kids. I also fought hard against opening the stores on Sundays." He doesn't consider himself especially religious but goes to mass every Sunday. "It's as much a tradition as anything else", he says. "I think that if we lose our religion we might lose other traditions. Going to mass on a Sunday, even if it just to spend time to stop and think of something other than the rush of everyday life is, I believe, important."

When he was first elected to the Seanad in 1993, he had no burning desire to blaze a trail in politics (his cousin is Labour's Ruairí Quinn). Initially, he wanted there to be "room in there for someone who was a doer". By then, Quinn had already worked for a decade (1979 to 1989) as chairman of An Post and he also set up the National Lottery. All the while, the supermarket chain continued to thrive.
"There is the danger now of people saying 'this is the wrong time to do anything'", he says. "But when I look back at the success stories of the '60s, '70s and '80s, people did start up businesses and they did succeed. So there are people who will succeed in tough times and there are people who will fail in good times."

This November, Feargal Quinn will be 74. He says that he is not overly concerned about his legacy ("I don't really care what people think of me in 50 or 60 years time") and looks as fit as a fiddle. He plays golf regularly, still runs upstairs and is working on a new book that started out as 'Six Lessons in Humility' but is now at 'Fourteen Lessons in Humility'. "I have no intention of retiring", he says. "I still get a great sense of achievement from the Seanad and one of the things that I have been working on for a few years is to get Ireland to join Central European Time. Then you would have an extra hour of daylight in the evening all year round."

Is this feasible? Well, if anyone can make the day seem longer, if not brighter, then Feargal Quinn is probably that man.