Last summer, Ford Kiernan and his comedy partner Greg Hemphill were soaring into the stratosphere. Not only did they have two enticing comedy film scripts filed away, and a Hogmanay special of their comedy hit Still Game scheduled for ­screening, they had an agreement in place to make a new BBC comedy series, Two Bob Rocket, set in space. But when Hemphill pulled out of their production company, Effingee, to go it alone, Kiernan’s dreams – along with the film scripts and the Still Game special – crashed and burned.

Where did that leave him? Well, very much alone, and with a hefty mortgage on a TV and film studio in Hillington, a production team and a wife and two children to support. There were commentators who reckoned that without Hemphill, the yin to his yang, his best friend and inspiration, Kiernan would never get off the ground again. But he did, first with a low-key lunchtime theatre drama in Glasgow and now with a new BBC sitcom, Happy Hollidays.

“This has been the toughest year of my entire career,” he admits. “I had to stabilise the business. And I had to prove I could write on my own, which is why I immediately wrote for the A Play, A Pie and A Pint lunchtime series at Oran Mor.” (The result was his homage to Frank Capra’s It’s a Wonderful Life, When Clarence Calls.)

“To be honest, it’s a shame Greg and I didn’t go on a bit further. And I was taken aback when he decided the business wasn’t for him. But I can be philosophical now. We had 10 years together and great success. And, looking back, the momentum had gone. As a result, I haven’t seen Greg in over a year, although we’ve spoken on the phone about business things.”

Will they ever get back together? “I don’t know. It was never a vitriolic break-up. So never say never. But there is a positive to emerge from all of this. I now own the studio outright, I’ve brought on new writers. I’ve shown I can fly on my own.”

At 47, Kiernan has not only survived: he’s thrived. First of all there’s Happy ­Hollidays, in which he stars alongside old pals Karen Dunbar and Gavin Mitchell (Still Game’s Boaby the Barman). Kiernan has also teamed up with the writer John Rooney, who created the best drama to come out of STV in years, High Times, to develop new television and film projects.

He certainly looks happy as he relaxes in the drawing room of his villa on Glasgow’s south side, to which he moved from the city’s west end. The worry lines have fled from his face and there’s a twinkle in his baby blues again. OK, he doesn’t have five cars in the driveway now, but he drives a nice, if rather old, Mercedes.

So how has he learned to fly solo and laugh in the face of adversity? Funnymen don’t always have the capacity to rebuild businesses, and showbiz creatures often have a gossamer-thin skin: they can’t cope with ­rejection and crushed dreams. “But I’m not a showbiz creature,” he replies with a wry grin.

No? Over the years he’s given the impression that he was one of those classic showbiz babies who viewed the midwife as his first audience; that when slapped on the backside he probably yelled: “Gonnae no’ dae that!” He’s told stories of how, as a schoolboy in his Dennistoun kitchen, he picked up American or Italian voices from his talented and funny single-parent mother, Frances, and of how they’d sing TV advert themes together. He’s admitted he was the archetypal class clown who would take off teachers and perform pastiches of chart comedy songs, where Miss Gibson would reappear as “the Funky Gibson”. By the time he was a teenager, he could produce more voices than a Blackpool clairvoyant.

But it seems there is another side to Kiernan. He’s business tough. Success, he says, was never about getting on the telly or making movies. It was about making money to buy toy cars, clothes and then real cars – even if it meant entering a world of chatlines, heavies and angry blokes with hunched backs.

“I never thought for a moment I could be a performer,” he says. “Right from a very young age I was always figuring out how to make extra cash. Me and my sister, Tracey, didn’t have pocket money in our house (his father left when he was three), so on a Saturday I washed cars. And it seemed perfectly logical to me to earn money this way. I built up the business – I even had two Jensen Interceptors on my wash – until I was subcontracting some of the motors out to other kids.”

Did the work ethic emerge from the realisation that he was the man of the house? Was he driven to spite his dad? “Don’t you go all Freudian on me,” he says with a wry grin. “I haven’t a clue.” But he admits there was a need to have things: toys, model cars and, later on, suits. “I think what I had was simply a determination to succeed,” he says. “I remember when I was about four or five watching a TV documentary about a young boy who was profoundly disabled. But this boy demonstrated he could tie his shoelaces, and I was entirely appalled that I couldn’t tie mine. I spent two hours working on it that night until I had it down pat.”

Kiernan doesn’t sleep well, a few hours each night at most. He’s been an insomniac since he was a child. “Sleep has always been an enemy to me, I guess. It deprived me of time when I could be doing or thinking. “Back at my first day at school in 1967 I was so geed up with excitement I hadn’t slept all night. But my mother got my intake day mixed up. I was due the next day, which meant we had to return home. And I can remember taking my Yo-Yo playpiece biscuit out of my new schoolbag and kicking it all the way up Sword Street in sheer frustration. And I still feel that same frustration. If I’m set to do something, it has to be that same day.”

It comes as no surprise, though, that the biscuit-kicker was a popular boy at school who could easily lead the 46 children in his class into anarchy. “One teacher, Miss McKenna, said to me that one day she’d come to the King’s to see me perform. She said I was the next Terry Scott. And I suppose with my chubby face I did look like him. But it never occurred to me I could go into entertainment. I performed for my mother’s pals doing Beechgrove Garden voices, but that was the extent of my expectations as a performer.”

At high school – “Just an inconvenience. Minimum effort” – Kiernan joined an opera class. “I was tried out with a couple of lines of Gilbert and Sullivan’s Iolanthe but I was hopeless. I got to sing, though, and I loved the whole experience. But entertaining as a career? No chance!”

This seems strange, given his talent and his chameleon abilities. Surely showbiz must have been lurking within the subconscious somewhere? Some basic need for endorsement, love, attention, girls? “If it was, I certainly didn’t know,” he says, laughing. What Kiernan did know was that he simply couldn’t wait to grow up. As a teenager he hung around with friends – lots of girls – at the likes of Coia’s Cafe in Duke Street near his home, listening to Queen’s Bohemian Rhapsody on the jukebox while eating chips and drinking coffee, because that’s what he thought adults did.

“My mother wanted me to stick in at school, she wanted something better than an apprenticeship for me,” he remembers. “And I did think once I could maybe be a cameraman, someone who could be filming John Toye one minute or James Bond the next, and earn lots of money.”

Money was always the central focus. He developed a window-cleaning round covering the high flats around Duke Street. “The windows tilted inwards, but most people couldn’t be bothered doing their own.” He also sold football cards, and by the age of 15 was driving a forklift truck (illegally) at a warehouse at Yorkhill quay. As soon as he left school, he went to work there full-time on £24 a week.

“The company also imported glass miniature bottles, and I smashed half a million bottles one day by accident. It took me three days to clear the mess up, but they never sacked me. It was a great job, and within minutes of leaving school I bought a Triumph Spitfire for £400. And I drove it up to the school yard.”

However, warehouses get cold in the winter, and Kiernan moved from the quay to join Tom Martin’s the tailors, where he could luxuriate in the glow of the Calor gas heater and flash a warm smile to customers. The bosses quickly realised the teenager had the chat and the upbeat persona to make a great salesman: he could shift mod suits and Ben Sherman button-down-collar shirts like they were going out of fashion. That’s why he wasn’t sacked, even after the Munro incident.

“Mr Munro was a regular and he came in to be measured up for a jacket,” Kiernan recalls. “But he had a hump. And I had to mark out the jacket with chalk, but I made a mistake and put the X on the wrong panel. As a result, the bulge for his hunchback was made on the wrong side. When he came in to pick up the jacket he went apeshit.”

Kiernan’s sales talents led to him being poached and moving through 14 menswear shops, increasing his salary to £32.50 a week and getting discount gear. He was more driven than a city taxi, and always opportunistic. One day in the depot of a leading car-repair chain, he discovered that old exhaust systems were being thrown into a tip. So he bought an old van, loaded up the exhausts and sold them on for scrap. Each week, he says, he made a small fortune.

Until, that was, the fighting began. He gives a wry smile. “As soon as you start something worthwhile, competition kicks in. Literally. I had my knuckles grazed a few times. Once, I arrived at the tip and this wee, crotchety old man was lifting the exhausts – my exhausts – into a van. So I yelled: ‘Right, whit are you daein?’ And he shouted ‘Kong!’ or something like that, and his boy came out. Ten feet of raw muscle. I stood my ground, but the writing was on the wall. These guys were real heavies.”

It was time to get out of Dodge, but Kiernan still hadn’t had the acting epiphany. He may have been a natural, yet drama school wasn’t even a possibility. But he did go to university. As a bar worker. Within months he was running all the bars at Glasgow University, staying for three years. “The tips were very good,” he says, ­grinning. But his relationship with his boss wasn’t. “He called me a b—,” Kiernan recalls. “In front of everybody. I’d pulled him up about his work rate and he had a go at me. But he was out of order so I thumped him.”

Thumped him? Thespians don’t thump people. They hit them with stinging barb – or, worse, assault them with indifference. And there would be a few more times in Ford Kiernan’s life (an anagram of his name, he throws in at this point, is Dark Inferno) when he’d take the non-vocal route to conflict resolution. “I know, but I’m much more even-tempered now,” he says with a resolute sigh. “But hey, the guy deserved it. He was bang out of order.”

So Kiernan was jobless – and, at 21, married with responsibilities. He became a security guard (like the central character in his play When Clarence Calls) simply to get a payslip to land a mortgage, but when he heard of a new Glasgow chatline company, pound signs flashed in front of his eyes. “I met the boss and told him I knew how to develop the business,” he recalls. And he was true to his word. Before long, the firm had opened in South Africa, London, Istanbul, Hong Kong and Madrid. Kiernan managed the chatline centre but also came up with chatline ideas such as staging computerised telephone horse racing. His was the Afrikaans voice punters heard when they called in. His was the voice of “the angry man”, an old Cockney pretending to be deaf, which took thousands of calls a day.

In a sense the chatline offices were theatre, with operatives taking on new personas. Indeed, in 1990 Kiernan’s office staff included hopeful comedians Bruce Morton and Stu Who?, the actresses Fiona Bell and Jenny McCrindle, and a man who was later to play a key role in his life, Greg Hemphill.

“Meeting Bruce was the pivotal moment for me,” says Kiernan. “Bruce thought I was funny and I should try my hand at stand-up.” So he did, beginning with a five-minute set at ­Blackfriars in Glasgow’s Merchant City, ­playing a ned character – a voice that would re-emerge in Chewin’ the Fat. This developed into a full set and sat delightfully incongruously against the City of Culture audience. “That was me hooked,” he recalls. “I couldn’t get enough of it.”

Yet that still didn’t mean he envisaged a career in comedy. Instead he spotted another money-making opportunity. He launched the city’s first karaoke night, at the Tunnel nightclub, and used his singing and gag-telling talents to pack the place for months on end. He also landed a job as a presenter on the now-defunct East End Radio, and soon found himself approached by radio and TV producers to do voiceovers.

The practical, business part of his brain hadn’t gone dormant, however. He bought a cafe in Busby, just outside Glasgow, “where I could glean my stand-up material and sell coffee”. And he bought the video shop across the road as well. A cloned Jack Horner couldn’t have had a finger in so many pies. But what was he? Businessman or entertainer? “Here’s the way I looked at it. Whichever job stood the tallest and punched its weight, then that’s what I’d do. I didn’t need to be a performer. I had seven projects on the go. If the cafe had been successful and I ended up with five more, I’d have been a cafe owner. If I’d become a national success as a stand-up, that’s what I would have done. Yet although I was making good money from all of them, I didn’t want to keep juggling. I wanted to see what had the most opportunity, what would grow organically. I was constantly weighing up.”

He still wasn’t sleeping, but he was having real fun with comedy. By this time remarried, to Lesley (“She’s fantastic, she’s dynamite, my balance in life”), Kiernan teamed up with John Paul Leach and the pair developed a double act, going on to write a play that was staged at the Edinburgh Festival Fringe. But Leach wanted to carry on with his medical career, and gradually Hemphill, thanks to Morton, came into the picture.

“I seemed to be in the BBC all the time, as was Greg, and we both landed the sketch comedy Pulp Video in 1995 with the likes of Bruce and Julie Wilson Nimmo. The show didn’t do a trick, but we started writing together and we wrote nine episodes of a children’s show called Hubbub, starring Elaine C Smith.”

This was a writing love story, a pair of ­opposites, the boy from Dennistoun and the Canadian immigrant, who complemented each other perfectly. Then came the play they wrote in a week, Still Game, featuring a pair of pensioners called Jack and Victor. “We started talking to each other in the voices and were so hot on the idea we just had to write the play.”

But should he drop the business activities to concentrate on comedy? Could being funny pay the mortgage on the west end flat? The play, he admits, was a last-ditch attempt to see if writing was indeed a pathway. And, as fate would have it, it went down a storm, laying the foundations for the Chewin’ the Fat radio and television series, and 44 sitcom episodes of Still Game. Kiernan was now officially a writer/actor. “I suppose I was,” he says, grinning. “It all turned right for me, but I think it’s kismet. And I couldn’t have planned it. The writing and the comedy came from my early experiences, my jobs, the people I’ve met. It all happened the way it was supposed to.”

These days he’s not walking into garages and coming up with cunning plans, but he still sees endless possibilities for making money. He loves changing, moving, fixing. He still ventures down different paths, but the paths these days are located within the funpark that is showbiz.

“John Rooney and I have some great ideas for drama, comedy and film,” he says. “And I’d like to do more acting, but I’ve come to realise that I’m a Timothy Spall type: in my forties, not very good-looking, the guy who doesn’t play the lead characters. I’d get the fat lawyers. So I’d like to concentrate on television and maybe create my own part. That means I get to write the words for my own mouth.”

Clearly, Kiernan has the grit and the talent to keep the little Culver-City-in-Hillington notion alive and well. “We’re renting out the studio regularly,” he says. “We made the TV ad (“Go greener”) featuring Gary Numan. How cool is that?”

And is his mother happy, now that he’s shifted from selling suits to selling out ­theatres and making television? “She’s dead chuffed I went into this game,” he says, revealing a warm smile. “In fact, a taxi driver told me recently he’d met her, and asked if she was pleased how her boy had turned out.

“She smiled and said, ‘Pleased? If I had a tail, I would wag it.’”

Happy Hollidays is on Fridays, 10.35pm, BBC One Scotland.