In May 1660, Charles II disembarked in front of cheering crowds at Dover, following a nine-year exile. He had been invited home by a parliament dismayed at the chaos caused by Oliver Cromwell's death and was warmly welcomed by a country weary of puritanism. He faced many hazards: his nation was divided by religion, its alliances were uneasy, its identity adrift.

The most astonishing thing about Charles II's reign was that it lasted a quarter of a century. His father had been beheaded, his brother would flee the country after only three years in power, and the Interregnum had left Britain overtaxed, resentful and exhausted. To maintain his position, he had to balance the interests of a mostly Anglican parliament and sizable minorities of Catholics and Presbyterians. He had to keep the Dutch and the French at bay and stay on top of a court full of intrigue. In his first decade alone, his promise of peace and prosperity was undermined by plague, fire and war.

Jenny Uglow made her name with biographies of artists and writers, inventors and scientists, notably The Lunar Men and her life of Thomas Bewick. She claims her sympathies naturally lie with "radicals and artisans protesting against the abuse of power" and acknowledges that, for her, plunging into the heart of the establishment to write about Charles II was disconcerting. But then she poses the question: "What if a person's art is also his life, his role simply 'being the king'?"

This seems a more useful way of getting at Charles than her ostensible organising principle, the king as a "gambler". Her chapters are organised under clubs, diamonds, hearts and spades and decorated (beautifully) with contemporary playing cards. But the narrative doesn't bear out the gambling interpretation. The stakes were high, but Charles didn't play them recklessly. He was a master of outward compliance and inward evasion, all coated in charm.

The book focuses on the first 10 years of his reign, on the grounds that his options narrowed subsequently. Charles comes across as calculating and pragmatic. He had learnt to dissemble in his years of penniless wandering around Europe's courts and, as one contemporary commented, had developed "the greatest art of concealing himself of any man alive". Amiable and open, yet prepared to be ruthless, this king who loved the theatre was always wearing a mask.

In one sense, this is frustrating for a biographer: where is the "real" Charles under all the womanising and sardonic humour? But contemporary readers are quite comfortable with the idea that there is no essentialist, non-performative self, that individuals are made up of the roles they play. And in this case the roles are endlessly fascinating because, to survive, Charles could never stop being the king. There was no such thing as private space.

This masterly, wide-ranging biography resists the temptation to take sides on Charles (who has variously been depicted in the past as the "merrie monarch" and a libertine let-down), though it is impossible not to find him appealing. He presided over a time of intellectual ferment and Uglow is at her best when she writes about Charles as the king of the dawning Age of Reason. There was much that was forward-looking and curious about him and she captures vividly the excitement of his arrival as a young, informal leader, European in outlook, fascinated by science, philosophy and women.

This period saw the founding of the Royal Society, the start of insurance and shipping in the City, and the tentative beginnings of a publicly voiced opposition that in time would replace court intrigue with party politics. Women could be immensely powerful and the king could father 12 children by different mistresses and go round Whitehall tucking them up at night.

Uglow casts her eye over everything in these 10 years, ably supported by the diarists Evelyn and Pepys, who provide her with much scurrilous background. I could have done with a bit more about Charles's latter years, in which he was forced to become more hardline. But this is a bravura biography, which leaves the reader with a vivid sense of what he did, and what he meant to the future.

Probably no man in our national history has excited so much enthusiasm and hope as did Charles II when he returned from exile in May 1660, invited by parliament to restore the monarchy after 11 years of republican rule. After the terminal disarray of the Cromwellian regime, so much was expected of Charles, yet he felt equal to the challenge and he had the almost universal support of the country. He had to establish his authority, take control of government, pay off and disband a large standing army, resolve the problem of confiscated estates and restore confidence and unity to a country that had lost its way. Most sensitively, he had to assure his new subjects that they would be able to worship in the way they wished. Religious differences had riven the country before the civil wars, diversity had increased during the republic, and toleration was now expected.

This is the scenario for the beginning of Jenny Uglow's latest book, in which she attempts to get the measure of the man who entered into his long delayed inheritance on that spring day in 1660. What can we know about his character, his intentions and desires? How would he enforce his political will? How would he reshape England? Uglow's method here is to observe the conduct of the king in the affairs of state and the affairs of the heart in the early years of his reign. She has plenty of material to draw on, for this is a very well-documented period, with spicy court memoirs, political recollections, and the diaries of John Evelyn and Samuel Pepys, the latter covering almost exactly the same years as her own book. Her sources allow her to give a balanced attention to the social scene and to the political bear-pit. Indeed, such was the passion for prurient gossip at this time that she can retrieve a remarkable amount of intimate information about the private lives of ministers, mistresses, actresses and priests, not to mention the ever-fascinating figure of the king.

Everything centres on Charles Stuart. He made himself an exceptionally accessible king, who might be encountered at the playhouse, or riding through the streets of London, stopping to chat with acquaintances. He could frequently be seen taking a brisk walk in St James's Park with his courtiers and advisers. He might go down to the dockyards to oversee naval business, or sail his yacht down the Thames. He opened up the precincts of Whitehall to visitors. His court was utterly different from that of his father, where refinement and protocol had set a restrained tone. Now there were style and wit in abundance, and beautiful women as never before. His mistresses, beginning with Barbara Palmer (who shines brightly in Uglow's narrative), satisfied his desire for sensation and pleasure. Charles was no romantic amorist: "His inclinations to love were the effects of health and a good constitution, with as little mixture of the seraphic part as ever man had," thought Lord Halifax. Catherine of Braganza, whom he had married in 1662 for money and an alliance with Portugal, proved to be an amiable consort  although she did not provide him with an heir  who adjusted her convent values to the erotic culture of Whitehall.

Religion clouded and distorted relations within the court and with the nation at large throughout his reign. Before his return, Charles had promised "liberty to tender consciences", unless differences of religion threatened the stability of the state. He seems sincerely to have desired toleration for dissenters, and maybe even for Catholics, but the parliament with which he had to work proved to be predominantly Anglican and increasingly hostile to the Presbyterians, Baptists, Quakers and other nonconformists, who made up a sizeable minority of the population. When parliament would not vote Charles money unless he agreed to ever more harsh measures against the dissenters, he submitted. With memories of the civil war still fresh, many MPs shared Lord Halifax's view that "It is impossible for a Dissenter not to be a Rebel". By 1664 there was virtually a reign of terror against them, with removal of civil rights, prohibitions against preaching, and large-scale arrest and imprisonment. Gone was the dream of a new, liberal England, with everyone gathered into a tolerant national church; instead, divisions were created that would never heal.

Charles's personal religion seemed a casual affair, but he gave many indications of being sympathetic to Catholicism. In 1670, he made the secret Treaty of Dover with his cousin Louis XIV, with an agreement that, in return for a very large sum of money, Charles would declare himself a Catholic at some convenient time. The French money came, but the convenient time did not, and Charles did not make his conversion until the very last hours of his life.

After the initial hopeful stage of Charles's reign, the state of the nation deteriorated steadily. The great plague of 1665 was followed a year later by the fire of London; misery deepened as the great frost produced the coldest winter for decades. The Dutch war was a shambles, culminating in that moment of national humiliation when a Dutch fleet sailed unchallenged into the Medway, and towed away the flagship of the English fleet. How Charles coped with these disasters and maintained his authority prompts Uglow into some serious thinking about his style of government and his political character. A ruthless streak came to the fore. Charles dismissed his chief minister Lord Clarendon, the man who had guided his policy in exile, planned his return, and been his principal negotiator with parliament. Now he was forced to take the blame for the plight of the nation. Other loyal supporters went too. He used his ministers as he did his mistresses, thought Halifax, discarding them when they had served their purpose. He determined to take more direct control of affairs, trusting his own judgment, and growing impatient with parliament. He envied his cousin Louis his absolute authority over France. Charles was arguably the last English monarch who had the potential to be an absolutist ruler, but he sensibly refrained from exercising the full reach of his power.

Uglow wants us to see Charles II as "a gambling man", who played for very high stakes. This is a motif that runs through her book, which is divided into sections with playing-card titles, illustrated with examples of contemporary cards. His greatest gambles, she thinks, were that he could get away with keeping mistresses as well as maintaining a queen, and that he could survive his eventual disclosure of his Catholic conversion. The book she has written, however, does not support this view of the king, who comes across as a much more pragmatic man than her title suggests. She recognises that "he was no man of stubborn principle, like his father or his brother James", and the adaptability resulting from that lack of principle was what allowed him to complete a full reign, unlike his father or brother. He compromised his ideal of religious toleration because he needed to live with parliament; he made war when it seemed politic to do so, and made peace when popular pressure demanded it. He sacrificed personal loyalty to political advantage on many occasions. Survival, not achievement, was the aim of his reign, and he attained his goal.

This is panoramic history of a high order. Uglow evokes the tumultuous events of the 1660s, and catches the feel of men and women living at the extremes of danger, pleasure and recklessness. The libertinism of the court, the violence of naval battles, the sufferings of those persecuted for their beliefs are all intensely conveyed. The enduring accomplishments are saluted too: the work of the Royal Society, the rise of a secular philosophy, the confident new architecture. Also recalled are the brilliant poets and dramatists who preserved the delights of fashion and wit in the amber of art. Yet from first to last it is the king who lives again through these pages, holding the age together, making his own history through calculation, compromise, whim and ingenuity. To understand how Charles learnt the difficult art of kingship, read this book.

 Graham Parry's Glory, Laud and Honour: The Arts of the Anglican Counter-Reformation is published by Boydell Press.