Late on the evening of 6 May, Alex Salmond took to the stage of a nightclub in Edinburgh's New Town and performed the kind of routine of which a professional stand-up comic would have been proud. A few hours earlier he had learned that he'd been re-elected First Minister of Scotland. That in itself was cause aplenty for celebration. But Salmond's and the crowd's unconfined jubilation was enhanced because the Scottish National Party (SNP) had not only gained the most MSPs, it now had an overall majority. Under the byzantine electoral system promoted by the Labour Party this was never supposed to happen. Now, amazingly, it had. In a parliament of 129 MSPs, the Nationalists had 69. Salmond's joy was overflowing.

Salmond was introduced by Angus Robertson, the SNP's leader at Westminster. As he drove that morning from Glasgow to Edinburgh across the Central Belt, it had occurred to Robertson that every constituency he was passing through was now held by the Nationalists. But, as ever, Salmond was able to trump his campaign director. Affecting a broad Scottish accent, which comes and goes depending on who he is talking to, Salmond said that a similar thought had occurred to him as he flew south from his own count in Aberdeen. "I was thinking that a' the seats I flew o'er in ma helicopter were yellow."

He had also realised, he added, that every seat in which Ed Miliband had campaigned had been lost by Labour. To raucous cheering, he said: "If you chart every stop on the trail of doom of Ed Miliband's individual constituency visits to inspire Labour activists who were somewhere on the streets of Scotland, the SNP won every one of the seats. Mind you, we won all the seats that weren't paid visits as well."

No one does hubris with more barefaced cheek than Salmond. When things are going well, his confidence, of which he has a surfeit, overflows. It is not blood that courses through his veins, a pundit once opined, but optimism. Keen gambler that he is, Salmond exudes hope, but it is born of pragmatism, not delusion. As a backer of horses, he studies form with the same intensity as he does the ramifications of the Barnett formula. Once upon a time, he and the late Robin Cook were rival newspaper tipsters. Cook may have known how to groom horses, Salmond claimed, but he knew better - as the racing records apparently showed - how to spot a winner.

His competitiveness is legendary. The only election he has ever lost occurred in the late 1970s, when he stood for the student presidency of St Andrews University - then, as now, as Conservative-inclined as the Monday Club. Ask Salmond by how many votes he was defeated and he reels the figure off with the chagrin of someone whose grief knows no bounds. His main opponent was called Bainbridge and throughout the campaign Salmond could not resist calling him Braindamage, something which, he later conceded, may not have helped his cause. Nor was he a generous loser When this was pointed out to him he quoted the racing driver Jackie Stewart: "Show me a gracious loser, and I'll show you a loser."

Some view his pugnaciousness as arrogance, others as archetypically Scottish. It is probably a mixture of both. In person, he is affable, engaged, witty, feisty, occasionally peppery, always eager to offer an anecdote. The worst a recent biographer could find to say about him was that he sometimes shouted at civil servants. His memory of facts and statistics is geekish. As a fan of Heart of Midlothian FC (Hearts), he can reel off the names of who played in what cup tie back to the days when footballs were made of leather and Bovril was the half-time drink of choice. As a golfer, he knows not only who won the Open championship where and in which year, but what they scored in each round. It is odd, therefore, that one of the criticisms levelled at him is his lack of attention to detail. Like Winston Churchill, he has a desire to win arguments and swat opponents with rhetoric and that tends to obscure his interest in the nitty-gritty of policy.

Fight on three fronts

What cannot be gainsaid, however, is that Sal­mond is - as much as any other political leader in a western democracy - the unchallenged and acknowledged star of his bailiwick. Moreover, he is popular. Polls consistently put him ahead of his party in terms of public approval and he is far more popular than the Nats' avowed aim of independence. Love him or loathe him, he cannot be ignored.

Opponents in other parties attempt to use his ubiquity to the SNP's detriment. Salmond, they insist, is a one-man band, the only soloist in the orchestra. A few years ago this was perhaps true. Today it smacks of desperation or, worse, complacency and denial. Were Salmond to fall under a bus, those lining up to become his successor might not be legion, but they would be several and serious, and would include his deputy, Nicola Sturgeon, and others such as Michael Russell, the education secretary, and the justice secretary, Kenny MacAskill - on whose say-so Abdelbaset Ali Mohmed al-Megrahi, the only person to have been convicted of the Lockerbie bombing, was released from prison in 2009.

Nor is Salmond unaware of this. At the outset of this year's election campaign, he said that the SNP proposed to fight it on three fronts: its record in government, its vision for Scotland and the quality of its "team". It was a gauntlet the other parties, most notably Labour, chose to disregard. Instead, the Scottish Labour leader, Iain Gray, preferred to concentrate his attack on the Tories at Westminster and the Cameron-Clegg coalition, even though it was pointed out repeatedly that they were not standing for election in Scotland. It was a huge tactical error. As the six-week-long campaign unfolded, the Nats moved from a distant second in the polls to command an insurmountable lead.

Time and again, it appeared it was Salmond, as much as his party, that the public supported; he was a gilt-edged asset in whom countless Scots were prepared to place their faith. In contrast to other party leaders in Scotland, he has the notable advantage of not having to look over his shoulder whenever he wants to say or do anything. When Labour is in need of ­succour in Scotland it sends for so-called big beasts such as Gordon Brown, Alistair Darling and Douglas Alexander. If Annabel Goldie, the erstwhile Conservative leader, wanted a shoulder to cry on, she could always depend on David Cam­eron, who is even less appealing to Scots than Margaret Thatcher. Meanwhile, the Lib Dem leader, Tavish Scott, tried desperately to distance himself from Nick Clegg, but to no avail. For his pains and for the loss of 11 of his 16 MSPs, he had no option but to resign. Was he, like Gray and Goldie, told by his southern masters that enough was enough?

For Scots, who perceive such interference as patronising, the signals that these moves send out are not reassuring. Salmond is far too savvy not to use this to his advantage. On BBC2's Newsnight recently, he asked Jeremy Paxman to allow him to finish his answer, after which Paxman would be free to patronise him. Such quick thinking endears him to Scots, who are constantly told they are not capable of managing their own affairs though other, even smaller nations appear perfectly able to do.

Similarly, the sight of expat Scots, such as the novelist Andrew O'Hagan, the historian Niall Ferguson or the professor of media Tim Luckhurst, denouncing the SNP and bemoaning the idea of independence only plays to Salmond's advantage. As he is well aware, nothing irks Scots so much as compatriots who've gone elsewhere telling those who stayed at home how they must vote. Salmond is happy with such adversaries, knowing that their influence achieves the opposite of what they intend.

Politics has been a way of life for Alex Salmond virtually since he was born nearly 57 years ago in Linlithgow, West Lothian - where, as he once told me, his putative biographer, "much of Scottish history was made and unmade". His parents were both civil servants, but the chief influence on his childhood was his grandfather, the town's plumber, who took him on tours spiced with tales from Walter Scott and Blind Harry. "For example, he showed me the ground where Edward I had camped before the Battle of Falkirk; he showed me the window from where the Regent Moray [James Stewart, 1st Earl of Moray] was shot dead in the street."

At primary school he savoured his first election victory after promising a free ice cream to those who voted for him. It is, say his critics, the kind of carrot he continues to offer without explaining fully how he intends to pay for it. As a schoolboy, he was unable to participate as much as he would have liked in sport because he was asthmatic. He made his biggest impact as a boy soprano. Singing the title role in Gian Carlo Menotti's Amahl and the Night Visitors, he received a warm review in the local newspaper and, had his voice not broken at the wrong moment, might have gone on to pursue a professional singing career. A novelty CD, released in 1999 to raise funds for the SNP, shows what a loss he was to the performing arts.

It was at St Andrews - long the most anglicised of the Scottish universities - where he studied medieval history and economics, that he joined the SNP after having an argument with a Labour-supporting girlfriend. On leaving university, he joined the department for agriculture and fisheries for Scotland and then worked for the Royal Bank of Scotland as an assistant to its chief economist. In 1981, he married Moira, who is 17 years his senior and who had been his boss in the civil service; the couple have no children. Then, in 1987, he ousted the incumbent Conservative MP for Banff and Buchan, Albert McQuarrie.

Back to Holyrood

It was the beginning of an enduring love affair with Westminster that he has never disguised, while attempting to disengage his country from it. Three years later he became SNP leader and a decade thereafter, having seen Scotland's parliament reconvened following a hiatus of 300 years, he stood down. At the time the decision was viewed with suspicion and fed rumours, which he revelled in acknowledging. He was, he told me on the day he announced his resignation, supposed to be terminally ill or have accumulated mountainous gambling debts or be having an affair with Sturgeon.

None was true. Salmond had always vowed to serve ten years as leader and, having done that, he intended to spend time reducing his golf handicap. In 2004, however, following John Swinney's resignation from the SNP leadership, he was back and determined to make the SNP the party of government. First, however, he had to win a seat that was far down the Nats' winnable list. His victory in Gordon, in north-east Scotland, with just over 2,000 votes to spare was symbolic, inspiring and typical, coming from behind in the polls to ease ahead in the final straight and romp lengths clear as the finishing line drew near.

It was a gamble that might have ended his career, had it not paid off. But it is at the root of Salmond's success, and those opposed to independence overlook it at their peril. These are the same people with the same tired and negative arguments who said a Scottish parliament would never work and that, if it did, there would never be a Nationalist government and that, if ever that came to pass, it would never in its wildest dreams have a majority of MSPs.

One by one, Salmond has overcome the odds to make all of these a reality. Who, four or five years hence and irrespective of what the pollscurrently predict, would bet against him delivering independence?

Alan Taylor edits the Scottish Review of Books