Much of George's life story is a catalogue of his romantic affairs, at least one of which endangered his succession to the throne. All of the Hanoverian monarchs were highly sexed, but George IV was probably the most profligate. It is not entirely clear why this should have been so. Unlike the relationship between George II and his son, George IV was not despised from birth. Quite the opposite. George III doted on him, and was reluctant for him to grow up. He was certainly spoiled but had an excellent education and was a quick learner. Perhaps this precocity, mixed with his good looks, made him too assured and confident of himself with a total disregard for how others viewed him. He was only sixteen when he had his first affair with the actress Mary 'Perdita' Robinson whom he saw in Shakespeare's The Winter's Tale in 1779. They remained together for a short while before George fell in love with another, and found he had to pay Mary a princely sum to keep her quiet. He worked his way through at least a dozen other mistresses over the next seven years, of varying degrees of high and low birth, and all costing him or the king a small fortune, until he encountered a young widow, Maria Fitzherbert, who was six years his senior. She became the one true love of his life. She refused to be his mistress, however, and George, in a typical immature tantrum, threatened to stab himself if she did not return his love. She eventually agreed to marry him. George knew that this was not possible. Not only was she already a widow (twice over) and pretty much a commoner (the grand-daughter of a baronet), but worst of all she was a Roman Catholic. The Act of Settlement of 1701 barred any Catholic from inheriting the throne, and it would effectively have barred George's accession. Moreover the Royal Marriages Act, which George's father had introduced in 1772, made any marriage by members of the royal family aged under twenty-five void unless it had received the formal approval of the king and the Privy Council. George acquired no such approval, but went ahead with the marriage anyway in December 1785. Under English law, George's marriage to Maria was void. The pope, however, regarded it as valid. George continued to have many more affairs, the most torrid of which was with the countess of Jersey. George III made every effort to control his son's debaucheries, for the prince, who now drank and ate to excess, was also becoming violent. He had spent to excess in building his own home at Carlton House in London, and as part of the arrangement for helping finance the debt, the king and Parliament insisted that George marry a proper wife. The King selected his niece, Princess Caroline of Brunswick. He must have been blind to her reputation, for not only was she not that attractive, and took little heed for her own personal hygiene, she was already supposed to have had one affair during her youth and, like George, she had wild tantrums. When the two first met three days before their wedding in April 1795, George felt sick at the sight of her and asked for a brandy, and Caroline called him fat and unhandsome. The Prince was drunk throughout his wedding ceremony and spent most of the wedding night in a stupor by the fire, but he must have done his duty, for nine months later to the day the Princess gave birth to their one and only child, Charlotte Augusta. George and Caroline separated soon after the birth and George denied Caroline any involvement in the raising of her daughter. Caroline established an orphanage in Kent in August 1797, whilst George went back to his mistresses. Mrs Fitzherbert returned to live with George for a while after 1800, still regarding herself as his lawful wife.

With the outbreak of the Napoleonic War, George applied several times for military service, jealous of the commands held by his brothers, but he was always refused. This was realistic, because the heir to the throne would no longer be put at such risk, but it was also pragmatic, as George had no military training and the government were fearful of what damage he might cause. Frustrated, George became mischievous at home. A dispute arose in 1804 over the custody of his daughter with the result that Charlotte was handed over to George 111. Annoyed at this, Prince George cast aspersions over the conduct of his estranged wife, alleging that one of the orphans in her care, William Austin, was her own son. This led to a "delicate investigation" by Parliament in 1806 which, though it cleared Caroline of the charge, revealed that her conduct was far from becoming.

In 1810, George III sank into his final decline and George was made Prince Regent, with certain restricted powers. Nevertheless from 1811 he acted as if he was the sovereign. His extravagance, even though curtailed by Parliament, was still lavish. During this period the Royal Pavilion at Brighton was completely rebuilt on the mock-Oriental style designed by John Nash. Under instruction from the Prince, Nash also redesigned Central London, which is why Regent's Park and Regent Street are so named. The streets of the City of London were lit by gas from 1814. Waterloo Bridge was opened in 1817 and Southwark Bridge in 1819. The Prince Regent continued to entertain lavishly, especially after the victory of Wellington in the Napoleonic Wars, when England played host to the emperor of Russia and the king of Prussia in June 1814.

The Regency period however was not all glitter. Soldiers returning from war were not fully recompensed and did not find gainful employment. There was considerable unrest which found little sympathy from the government, especially from Lord Liverpool and Lord Sidmouth, who had previously dealt harshly with the Luddites. A gathering at Spa Fields in North London in December 1816, when manufacturers sought to present their views to the Prince Regent, turned ugly and was dealt with severely. Sidmouth used this as an opportunity to undertake what became called the Green-Bag inquiry in February 1817 when a series of secret committees looked into a number of alleged cases of sedition. As a result of this habeus corpus was suspended. A gathering in St Peter's Field in Manchester in August 1819 alarmed the authorities because of its size - the military dispersed the meeting, causing over four hundred injuries and eleven deaths. This incident became known as Peterloo (after Waterloo) and led to even more repressive legislation outlawing public assemblies. The populace were not happy and within only a few weeks of the Prince Regent becoming king in January 1820, a plot was unearthed, known as the Cato Street Conspiracy to assassinate the members of 'he Cabinet and overthrow the Government.

George had other things on his mind, however. He had been grief-stricken when his only daughter, Charlotte, who had married in May 1816, died due to complications after childbirth in November 1817. He now had no heir to the throne, and his wife, Caroline, who was now approaching fifty, was past childbearing age. In fact George did every-thing to keep Caroline out of the country. She had gone on a grand tour of Europe after the end of the Napoleonic Wars and was by all accounts romantically involved with an Italian courtier, Bartolomeo Pergami. However, on George's accession to the throne Caroline was determined to return and take her place as queen. George offered her £50,000 a year to stay away, but she brushed this aside and returned to Britain in June 1820. George introduced a parliamentary bill, called the Bill of Pains and Penalties, which was an enquiry into Caroline's conduct. Since Caroline appeared in the House of Lords, the enquiry has come to be regarded as her trial, though she never spoke in her defence. The bill was dropped and Caroline exonerated with much public rejoicing. George still refused to admit her and went to great pains to exclude her from his coronation in July 1821. George had ensured no expense was spared over this event which he planned for over a year and it remains the most extravagant coronation ever held in England. To George's relief, but also his shame, Caroline died just three weeks later on 7 August 1821 of inflammation of the bowels. The public had always been very supportive of the queen and voiced strong opposition to the king. A few weeks later George went on a royal progress through the kingdom, visiting Ireland and, at the urging of Sir Walter Scott, Scotland (the first Hanoverian to do so). He put on all his charm and elegance and was remarkably well received. One might question how much the populace were celebrating the continuance of the monarchy as distinct from the individual. The institution of the monarchy suffered considerably under George IV, but survived sufficiently due to the fond memory of George III to enter a golden phase under Victoria.

George's reign as king lasted for just over ten years and it advanced the country but little. George had a succession of prime ministers, most of whom he tried to oppose, especially as regards their foreign policy. Both he and the duke of Wellington vigorously opposed any political reform and it was only with reluctance on their parts that, at last, in April 1829 the Catholic Emancipation Act became law, restoring to Catholics the right to public office. It did not meet with the riots accorded earlier attempts to do this. There were greater troubles besetting the nation than religion, and it required a much stronger government than George IV and his ministers to tackle them. George died on 26 June 1830 of respiratory problems, aged sixty-seven. For all his dandyism and extravagance he was at the end a sad and lonely man, who had damaged the stature of the monarchy and whose only lasting legacy is the Brighton Pavilion. He was succeeded by his brother, William IV.