He was a nephew of Thomas Villiers, 2nd Earl of Clarendon and John Villiers, 3rd Earl of Clarendon. Both were elder brothers of his father and were childless at the time of their deaths. On 22 December, 1838, George became the Earl of Clarendon following the death of his last paternal uncle.
His paternal grandparents were Thomas Villiers, 1st Earl of Clarendon and his wife Lady Charlotte Capell. His maternal grandparents were John Parker, 1st Baron Boringdon and Theresa Robinson. Theresa was a daughter of Thomas Robinson, 1st Baron Grantham and his wife Frances Worsley
Thomas Villiers was the second son of William Villiers, 2nd Earl of Jersey and his wife Judith Herne, daughter of Frederick Herne. His wife Lady Charlotte Capell was the eldest daughter of William Capell, 3rd Earl of Essex and Lady Jane Hyde. She was the heiress to the Hyde family who previously held the title of the Earl of Clarendon. On 14 June, 1776, the earldom was revived in favour of her husband. The connection with the Hyde family was therefore by the female line and somewhat remote.
Lady Jane Hyde was a daughter of Henry Hyde, 4th Earl of Clarendon and Jane Leveson-Gower. Her paternal grandparents were Laurence Hyde, 1st Earl of Rochester and Lady Henrietta Boyle. Her maternal grandparents were Sir William Leveson-Gower, 4th Baronet and Lady Jane Granville.
Rochester was the second son of Edward Hyde, 1st Earl of Clarendon and his second wife Frances Aylesbury. His sister Anne Hyde was the first wife of James II of England, mother of Mary II of England and Anne of Great Britain.
Elizabeth Brooke was a daughter of William Brooke, 10th Baron Cobham and his second wife Frances Newton.
Young George Villiers entered upon life in circumstances which gave small promise of the brilliance of his future career. Certainly, he was well born; he was heir presumptive to an earldom; his mother was a woman of great energy, admirable good sense, and high feeling. But the means of his family were contracted; his education was desultory and incomplete; he lacked the advantages of a training either at a public school or in the House of Commons. George went up to Cambridge at the early age of sixteen and entered St John's College on June 29, 1816. In 1820, as the eldest son of an earl's brother with royal descent, he was able to take his M.A. degree under the statutes of the university then in force. In the same year, he was appointed attache to the British embassy at Saint Petersburg. There he remained three years, and gained that practical knowledge of diplomacy which was of so much use to him in later life. He had received from nature a singularly handsome person, a polished and engaging address, a ready command of languages, and a remarkable power of composition.
Upon his return to England in 1823, he was appointed to a commissionership of customs, an office which he retained for about ten years. In 1831, he was despatched to France to negotiate a commercial treaty, which however was fruitless. On 16 August, 1833, he was appointed minister at the court of Spain. Ferdinand VII died within a month of his arrival at Madrid, and the infant queen Isabella, then in the third year of her age, was placed on her contested throne, based on the old Spanish custom of female inheritance. Don Carlos, the late king's brother, claimed the crown by virtue of the Salic Law of the House of Bourbon which Ferdinand had renounced before the birth of his daughter. Isabella II and her mother Christina, the queen regent, became the representatives of constitutional monarchy, Don Carlos of Catholic absolutism. The conflict which had divided the despotic and the constitutional powers of Europe since the French Revolution of 1830 broke out into civil war in Spain, and by the Quadruple Treaty, signed on 22 April 1834, France and England pledged themselves to the defence of the constitutional thrones of Spain and Portugal. For six years Villiers continued to give the most active and intelligent support to the Liberal government of Spain. He was accused, though unjustly, of having favoured the revolution of La Granja, which drove Christina, the queen mother, out of the kingdom, and raised Espartero to the regency. He undoubtedly supported the chiefs of the Liberal party, such as Espartero, against the intrigues of the French court; but the object of the British government was to establish the throne of Isabella on a truly national and liberal basis and to avert those complications, dictated by foreign influence, which eventually proved so fatal to that princess. Villiers received the Grand Cross of the Bath in 1838 in acknowledgment of his services, and succeeded, on the death of his uncle, to the title of Earl of Clarendon; in the following year, having left Madrid, he married a young widow, Lady Katharine Foster-Barham (née Grimston), eldest daughter of James Grimston, 1st Earl of Verulam.
In January 1840 he entered Lord Melbourne's administration as Lord Privy Seal, and from the death of Lord Holland in the autumn of that year Lord Clarendon also held the office of Chancellor of the Duchy of Lancaster until the dissolution of the ministry in 1841. Deeply convinced that the maintenance of a cordial understanding with France was the most essential condition of peace and of a liberal policy in Europe, he reluctantly concurred in the measures proposed by Lord Palmerston for the expulsion of the Mohammed Ali of Egypt from Syria; he strenuously advocated, with Lord Holland, a more conciliatory policy towards France; and he was only restrained from sending in his resignation by the dislike he felt to break up a cabinet he had so recently joined.
The interval of Sir Robert Peel's great administration (1841-1846) was to the leaders of the Whig party a period of repose; but Lord Clarendon took the warmest interest in the triumph of the principles of free trade and in the repeal of the corn laws, of which his brother, Charles Pelham Villiers, had been one of the earliest champions. For this reason, upon the formation of Lord John Russell's first administration, Lord Clarendon accepted the office of President of the Board of Trade. Twice in his career the governor-generalship of India was offered him, and once the governor-generalship of Canada; these he refused from reluctance to withdraw from the politics of Europe. But in 1847 a sense of duty compelled him to take a far more laborious and uncongenial appointment. The desire of the cabinet was to abolish the lord-lieutenancy of Ireland, and Lord Clarendon was prevailed upon to accept that office, with a view to transform it ere long into an Irish secretaryship of state. But he had not been many months in Dublin before he acknowledged that the difficulties then existing in Ireland could only be met by the most vigilant and energetic authority, exercised on the spot. The crisis was one of extraordinary peril. Agrarian crimes of horrible atrocity had increased threefold. The Catholic clergy were openly disaffected. This was the second year of the Irish famine, and extraordinary measures were required to regulate the bounty of the government and the nation. In 1848 the revolution in France let loose fresh elements of discord, which culminated in an abortive insurrection, and for a lengthened period Ireland was a prey to more than her wonted symptoms of disaffection and disorder. Lord Clarendon remained viceroy of Ireland till 1852. His services were expressly acknowledged in the queen's speech to both Houses of Parliament in September 1848—this being the first time that any civil services obtained that honour; and he was made a Knight of the Garter (retaining also the grand cross of the Bath by special order) on 23 March 1849.
Upon the formation of the coalition ministry between the Whigs and the Peelites, in 1853, under Lord Aberdeen, Lord Clarendon became Secretary of State for Foreign Affairs. The country was already "drifting" into the Crimean War, an expression of his own which was never forgotten. Clarendon was not responsible for the policy which brought war about; but when it occurred he employed every means in his power to stimulate and assist the war departments, and above all he maintained the closest relations with the French. The tsar Nicholas had speculated on the impossibility of the sustained joint action of France and England in council and in the field. It was mainly by Lord Clarendon at Whitehall and by Lord Raglan before Sevastopol that such a combination was rendered practicable, and did eventually triumph over the enemy. The diplomatic conduct of such an alliance for three years between two great nations jealous of their military honour and fighting for no separate political advantage, tried by excessive hardships and at moments on the verge of defeat, was certainly one of the most arduous duties ever performed by a minister. The result was due in the main to the confidence with which Lord Clarendon had inspired the emperor of the French, and to the affection and regard of the empress, whom he had known in Spain from her childhood.
In 1856 Lord Clarendon took his seat at the congress of Paris convoked for the restoration of peace, as first British plenipotentiary. It was the first time since the appearance of Lord Castlereagh at Vienna that a secretary of state for foreign affairs had been present in person at a congress on the continent. Lord Clarendon's first care was to obtain the admission of Piedmont-Sardinia to the council chamber as a belligerent power, and to raise the barrier which still excluded Prussia as a neutral one. But in the general anxiety of all the powers to terminate the war there was no small danger that the objects for which it had been undertaken would be abandoned or forgotten. It is due entirely to the firmness of Lord Clarendon that the principle of the neutralization of the Black Sea was preserved, that the Russian attempt to trick the allies out of the cession in Bessarabia was defeated, and that the results of the war were for a time secured. The congress was eager to turn to other subjects, and perhaps the most important result of its deliberations was the celebrated Declaration of the Maritime Powers, which abolished privateering, defined the right of blockade, and limited the right of capture to enemy's property in enemy's ships. Lord Clarendon has been accused of an abandonment of what are termed the belligerent rights of Great Britain, which were undoubtedly based on the old maritime laws of Europe. But he acted in strict conformity with the views of the British cabinet, and the British cabinet adopted those views because it was satisfied that it was not for the benefit of the country to adhere to practices which exposed the vast mercantile interests of Britain to depredation, even by the cruisers of a secondary maritime power, and which, if vigorously enforced against neutrals, could not fail to embroil her with every maritime state in the world.
Upon the reconstitution of the Whig administration in 1859, Lord John Russell made it a condition of his acceptance of office under Lord Palmerston that the foreign department should be placed in his own hands, which implied that Lord Clarendon should be excluded from office, as it would have been inconsistent alike with his dignity and his tastes to fill any other post in the government. The consequence was that from 1859 till 1864 Lord Clarendon remained out of office, and the critical relations arising out of the Civil War in the United States were left to the guidance of Earl Russell. But he re-entered the cabinet in May 1864 as Chancellor of the Duchy of Lancaster; and upon the death of Lord Palmerston in 1865, Lord Russell again became prime minister, when Lord Clarendon returned to the foreign office, which was again confided to him for the third time upon the formation of Gladstone's administration in 1868. To the last moment of his existence, Lord Clarendon continued to devote every faculty of his mind and every instant of his life to the public service; and he expired surrounded by the boxes and papers of his office on June 27, 1870. No man owed more to the influence of a generous, unselfish and liberal disposition. If he had rivals he never ceased to treat them with the consideration and confidence of friends, and he cared but little for the ordinary prizes of ambition in comparison with the advancement of the cause of peace and progress.