When Alex Salmond was a boy, his father was a Labour voter, and his mother a Tory. One of his earliest memories is of his dad backing Harold Wilson in the 1964 election, while his mum, the daughter of a headmaster, thought Sir Alec Douglas-Home looked much more how a Prime Minister should.

And, then, in one election, a Labour canvasser came to their door on a Linlithgow council estate. His father joked that the party would have his vote, but his wife was lost to the Conservatives. "That's OK," said the canvasser, as Salmond recounts it. "Just as long as she's not voting for the Scottish Nose Pickers."

Now, Robert Salmond's golfing partner was a miner who, unfashionably at the time, was a staunch Scottish Nationalist Party supporter. Salmond reacted angrily to the childish slight on his friend. Half an hour of doorstep argument later, he told the Labour activist he would never vote for the party again, and he became a lifelong nationalist.

"He is quite thrawn," says his elder son, now the First Minister of Scotland, his eyes twinkling beneath beetling eyebrows.

The Scottish Labour Party – now scrabbling around for its fifth leader since devolution 10 years ago amid terrible poll ratings and after a devastating defeat at Glasgow East with a 22 per cent swing to the SNP – has been scoring spectacular own goals for more than 40 years, born, some would say, of complacency.

But this heated contretemps may rank as the worst of all – it made Salmond Snr a nationalist; was central to his son following suit; Salmond Jnr has somehow succeeded in making the SNP an electoral force; and – who knows? – it all might just end up with the demise of the Union.

Alex Salmond is in ebullient form when we meet at the Palace Hotel in Peterhead, a fishing community on the north-east coast. In truth, he probably is never anything else. He has an easy manner, a ready laugh and – his opponents say – a certain air of being pleased with himself. Is it smugness? Or self-confidence?

We Scots, of course, hate that sort of thing. "Nobody likes a smart arse" could be the mantra of the nation – and it must have been that very thought which ran through his father's head during his doorstep conversion four decades ago.

But here is Salmond, 15 months into running a minority SNP administration (it has just one seat more than Labour) with consistent opinion poll leads and almost universal acclaim. Scots seem to take some pride in the fact Salmond is our "smart arse". The brilliance of his strategy – or is it just serendipity? – is that he is now both the boss, Bute House occupant (but fighting the odds against the parliamentary arithmetic), and an underdog, Westminster irritant.

So, what's the secret, Alex?

"It's not to pretend you can do everything, but if people like you – in the sense of admiring or having respect for what you are trying to do – then they will understand the odd blemish. If people don't like you, and lack confidence in what you are trying to do, they won't forgive you anything. That is what happened in Glasgow East. People like the SNP government. Not because they agree with everything we are doing, but they think we are trying our best, getting on with the job with a business-like approach and with a vision for the country. If they like the cut of your jib, they will forgive you the odd lapse. Whereas if they don't like you, and think you are depressed and fretting, they will forgive you nothing, and that's the state the Prime Minister has got himself into. The attitude to politics and governance is incredibly important, and I think we have hit the right note."

One of the great, unexpected pluses, he says, was the Liberal Democrats' refusal to form a coalition. The sticking point was the SNP's manifesto pledge to hold a referendum on independence during this parliament.

"I was pretty miffed about it. I was led to believe on election night by Nicol Stephen, the Lib Dem leader, that an arrangement was possible. Am I miffed now? No! It's the best thing that could have happened. We were saved! We were saved!

"I can't claim to have any great insight beforehand. I believed we would be better with a majority, that we needed to have the assurance of being able to win every key vote. But dealing with the Liberals, it was like trying to grab quicksilver. The way it has turned out has been absolutely the best thing that could have happened to us. We have been able to govern much more quickly, much more decisively."

There have been criticisms over as yet unfulfilled manifesto pledges: increases in the numbers of police officers, reduction in school class sizes and the replacement of the council tax with a local income tax. And, some pundits suggest, the Salmond administration has shied away from major legislation because of the arithmetical difficulties, concentrating instead on "not scaring the horses".

"Not tackling the big issues? My goodness. We have knocked up quite a few achievements in the first year. We've cut prescription charges, frozen council tax and drastically reduced rates for small business. Good thing we did, too. The timing of this was immaculate, for Scotland is more resistant – not immune by any means – to the economic downturn.

"We're improving relations between central and local government; have in place the first drugs strategy for a quarter of a century; and we have embarked on the hugely controversial campaign against Scotland's addiction to the bottle. Self-evidently, that should have been done a generation ago and has been ducked and weaved and neglected and ignored and laughed at. Whatever else you might say about us, we are certainly not afraid of taking on vested interests – there is no bigger vested interest than the retail and alcohol lobby in Scotland.

"Come on, this is big stuff. These are all tackling underlying issues – it's not just a question of striking and populist announcements."

Where to now?

"I believe we can win a referendum in 2010. We have the political engine behind us. We have a public that is willing to listen to the arguments we are putting forward, and we will gain converts to those arguments. We believe people will come to the right conclusion. We trust them.

"In Glasgow East, our ace card was the governance of Scotland over the past 15 months under SNP control. In the referendum, it will be the governance of Scotland over three years, and the credibility and authority that comes from that."

At every stage until then, Salmond will claim ownership of the achievements in Scotland. And, where it goes sour – when the economy bites – that will be the fault of the Brown administration in London. And, of course, the general election will come before the referendum.

"My favourite is a hung parliament with 20 SNP MPs. I want to be calling the shots, organising the tune."

Despite Salmond's assertion that internal canvassing suggests otherwise, opinion polls have yet to demonstrate that the approval ratings for the SNP are translating into anything approaching majority support for independence. There is, though, no guarantee that the Scottish Parliament will vote to have the referendum, and that may well be his get-out-of-jail-free card.

For lose the referendum, and where does he – and nationalism – go? But continue to enjoy high approval ratings in government, continue to supplant Labour with a left-leaning agenda, increase his majority next time round at a time the Tories rule at Westminster or there is a hung parliament, and more and more power is likely to be ceded to Holyrood. He has been called a constitutional gradualist, and his softly-softly approach is delivering, big time.

It is, though, when the chat turns from politics to his upbringing that you can imagine the making of the man.

He says of his parents' golden wedding anniversary: "I hadn't heard my father make a speech in his life. He stood up there without notes for half an hour and was full of stories about their life together and how he came to ask her out. He plucked up the courage to go to the Ministry of Pensions office where she worked. She sent him away with a flea in his ear because his hair was too long. So he went up to the barber's, and 20 minutes later re-presented himself. She relented because she thought it was so funny."

The Salmond home was a politically aware household: Panorama was on, they would discuss the news and current affairs, and a memory he savours is of each Hogmanay – his birthday – when the talk in the small hours turned political. His dad, the lone nationalist, would be forced to defend his views.

His love of golf – he still plays off 18, and chuckles at the memory of winning a pro-am tournament last year at Inch, where Gordon Brown is honorary president – he got from his father, who took it up when his son was three just to give him a good start. The result, says Salmond, is he has "a beautiful swing, a wonderful swing, but I can't chip or putt any more".

And, he says after recounting a Jack Nicklaus anecdote about the slippery ways on the course of ex-President Clinton, he could never cheat. "No matter the lie, even if I was on my own, I'd have to play it. I can hear my dad saying: 'Play the ball as it lies.' Because of the way I was taught, I would feel awful about it. I don't know if that makes me dead honest or dead stupid."

He speaks warmly of his grandfather, a plumber. He was his apprentice, and – believe it or not – he can still turn his hand to it. And his interest in horse-racing was sparked by his uncle. He still remembers crowding round the television for his first bet – half a crown when Arkle won the Gold Cup in 1964. He used to write a successful tipping guide for The Scotsman and was a regular on Channel 4's The Morning Line.

What of the rumours that dogged the 1999 election campaign – that he had big gambling debts? He refuses to say what his largest loss to the bookmakers has been, and answers: "Do you think if there was a scintilla of truth in all of that, the press would never have found out?"

He speaks so fondly of his two sisters and his younger brother that I wonder if he regrets not having children of his own. His wife Moira, a former civil servant and low-key First Lady, is 17 years older than he is. He shrugs off the question as if it is daft. There is, he says, no point in thinking of all that.

No tale from Scotland is complete without a football story. Only this morning, Salmond, a fervent Hearts fan, has been critical of the SFA's decision to sell the television rights to Scotland's home matches for the next six years to Sky. In this there is no doubt a populist touch, but does it play into the idea that when the national team is going well – near qualification for Euro 2008 meets the definition – so too does the SNP? "There may be something in it. A feel-good factor is good for the SNP. When Andy Murray wins the Olympics, it will be a good thing for the SNP because it will make people feel good about the country."

Salmond denies he is a one-man band, and one cabinet minister told me recently that the SNP government is more competent than the previous Labour administrations in Edinburgh. But there is no denying that his unquestionable abilities are the key to the changing landscape north of the border. Could one man's force of character really signal the break-up of the UK?

For now, though, he will settle for being a good First Minister adept at playing the system. Unless he gets too cocky – always a possibility – he is in a win-win situation. And maybe that's what success-starved Scots respect about him most.

Biography

1954: Born on 31 December to civil servants Robert and Mary Salmond, the second of their four children.

1973: Joins the SNP while at the University of St Andrews, from where he graduates with an MA in economics and history.

1980: Joins the Royal Bank of Scotland as an economist, and works there for seven years.

1981: Marries Moira McGlashan, a senior civil servant in the Scottish Office. He is 26; she is 43.

1985: Elected SNP's Vice Convener for Publicity after a spell of being suspended from the SNP for membership of the left-wing 79 Group.

1987: Elected MP for Banff and Buchan.

1990: Elected leader of the SNP, succeeding Gordon Wilson.

1998: Campaigns for devolution alongside Donald Dewar.

1999: Elected to Scottish Parliament, but the SNP loses the election.

2000: Stands down as leader.

2001: Leaves Scottish Parliament to concentrate on life at Westminster.

2004: Wins leadership again after change of heart.

2007: Elected to the Scottish Parliament, and fails to form a coalition with Liberals Democrats. Becomes First Minister of a minority administration.

2008: SNP wins Glasgow East, Labour's third safest seat in Scotland with a 22% swing.