Cyril Cullen has sold his knitwear designs in Saks and Bloomingdales, but it all started with a game of golf, he tells Deirdre McQuillan

Designer Cyril Cullen made an international career out of a 10-shilling bet. Cullen was part of a creative wave of knitters in the 1970s who elevated a domestic craft into sophisticated fashion. At the height of his success he employed some 1,200 knitters and was probably better known all over the US than in Ireland. "He was ahead of his time," says Cullen's daughter Margot, who has written a book celebrating his life and work.

Today his production is limited to handknits made by a small group using wool from his flock of Jacob sheep, as his interests have given way to designing and making porcelain, as well as restoring 15th-century Farney Castle in Tipperary where he and his family now live and operate a visitor centre. "It's a new phase in our lives," he says.

Sitting in the handsome drawing room of Farney beside a grand piano, Cyril Cullen cuts a striking figure in a linen suit, striped shirt and handwoven crios tie. He seems slightly abashed by the attention, more interested in talking about his family than himself. He shows me his latest knit, a batwing sweater with an ancient Celtic design, the pattern for which he tells me he has traced back to lower Egypt. "Knitting is very calming and relaxing," he says.

Born in Fermoy, Co Cork, to a musical family, he went into the civil service after his Leaving Cert, working initially in Dublin, later moving to Letterkenny, Co Donegal. It was there in 1960 that the event occurred that was to alter the course of his life. Out golfing with a mixed foursome, he took a 10-shilling bet that he could knit a sweater in a week. "I said I could do it standing on my head." By midnight he had the stitches on the needles, and the following Thursday the sweater was complete. It sowed the seeds of an idea, far-fetched at the time, that this was something from which he could make a living.

"I studied the history of knitting and discovered that men had done it for 1,500 years and in those days it took six years to qualify. I realised I was not a freak, but a throwback, and I became, as the Americans would say, a closet knitter." He made sweaters in new designs for his brothers and sister, and was one of the first to modernise the Aran knit. Transferred to Lismore, he trained a choir and assembled six volunteer knitters.

The big break came when Adele Astaire (Fred Astaire's sister), who was living in Lismore Castle, heard of his work and asked to see him. "I cycled down with a bag of knitwear. 'You are the second Balenciaga,' she exclaimed and we became great friends. She introduced her guests to me, people like the Kodak heiress, Mrs Sybil Harrington, Lady Orr Lewis, the Duke and Duchess of Devonshire, the Kennedys and others - I was making ski wear and après ski wear, capes, sweaters and jackets. People only thought of knitwear then as a twinset or a sweater, they didn't realise it could be for after five or skiwear."

After a big order from the duty-free shop at Shannon airport, he quit the civil service and turned his hobby into a business. He was also making his name on television and designing patterns for top spinning companies. In 1967 he moved to Carrick-on-Shannon, to a Georgian house which became his home, studio and workshop for nearly 30 years. In 1972 he married Margie Lee from Blarney, a civil servant who had trained as a model; he made her silk and crochet veil and "Juliet" cap for the wedding.

His knitted "hoodie" dresses, three-piece suits and kaftans from the mid-1970s seem extraordinarily modern today. A complex handknitted frill was his signature motif and his "Irish Mink", a cream wool wrap in trinity stitch and cable, was another invention. "Whatever I design for a handknit, it is something that cannot be done by machine because I know the limitations of machinery. Machines can't knit into the back of a stitch, for example," he explains.

Twice a year he travelled to New York as well as the European Fashion Fair, selling to Harrods, Lord & Taylors, Saks, Bloomingdales and other upscale department stores. In Ireland his knitwear was sold in Switzers and Shannon airport. He became a good friend of the late Eleanor Lambert and Sybil Connolly and met Yves St Laurent, Pierre Cardin, Jackie Kennedy and Salvador Dali.

He was nominated by Women's Wear Daily to present his collections in the former Yugoslavia three years in succession, and his wife modelled both his clothes and those of the Russians. Margie laughs when she recalls that the Russians told her to "walk like a snake". Other invitations followed, but by this time his musical daughters, the award-winning Cullen Harpers, were also in demand worldwide - one, even at six years old, had appeared on the Late Late Show.

"My family came first in all situations," he says. He did, however, accept an offer in 1978 to go to Lesotho to teach Basotho women how to knit, and developed patterns with them that reflected their own environment. Today, there are around 4,500 knitters in Lesotho.

But 26 years of transatlantic travel eventually took their toll. "You can't keep going at a high pace forever. I kept saying I needed to do something else. So I decided to do porcelain, to have a second arrow to my bow."

In 1995 the family moved to Farney where he installed a kiln and set about mastering the craft. Now he produces figurines, ornaments, vases and even buttons for his knitwear in a light duck-egg blue porcelain, sold in the castle shop.

A self-effacing man, he dismisses his achievements with a wave of the hand. "Most things in life can be done by people of average intelligence. I am self-taught in everything. There is a lot of maths in knitting and you have to take account of the stretch of a dress, but as you work you are building something and in your mind, it leads you on. I like the fact that I am doing other things now like gardening that I didn't have time for before."

His wife and four daughters are a particular source of pride. "We all adore each other all the time in this house," he says. Margie has just completed a master's degree on Irish music as a rural resource. Margot, author of the book, is an architect, Emily lectures in English and is working on a PhD on the semiotics of the harp, Benita is a GP and Tara has just qualified as a barrister. Music is central to their lives. "I believe every child should be taught music because it develops a sensibility to so many things you can enjoy in this world," he says.

Surrounded by a collection of harps, Cullen is playful as he poses for the camera, a cone of cream wool at his feet. He hopes the book will inspire others. "I believe in taking a chance and going for it. If you get an idea, research it, and if you convert it into a dream, you can follow your dream like I did."

Knot Sure by Margot Cullen will be published by Blackwater Press next Monday, €20. Cyril Cullen will be demonstrating at The Knitting and Stitching Show, in the RDS, Nov 3-6