George Canning was the son of George Canning Senior, a younger son of an old Irish family, and of Mary Anne Costello. He was born in Marylebone in 1770. His father died young, and his mother went upon the stage and made two successive imprudent marriages. The boy was brought up at the expense of his uncle, Stratford Canning, a Whig banker in London, who sent him to Eton, where he displayed scholarship and wit, and earned literary fame. At Christ Church, he won the Latin Verse prize and became the lifelong friend of Robert Jenkinson, afterwards the second Lord Liverpool. He then entered Lincoln's Inn and was probably intending to seek a seat in Parliament, as a follower of Fox, when he suddenly changed his opinions, at the end of 1792, and declared himself for Pitt. Lord Holland told Greville, in 1834, that he had been, at that time (1792), one of Canning’s most intimate friends and that Canning was then "a great Jacobin, much more so than he was himself"; that Canning had always hated the aristocracy, a hatred which, says Greville, "they certainly returned with interest". But the truth is that the year 1792 was one in which any reasonable Whig would readily change his opinions and there is no reason to doubt the sincerity of Canning’s conversion. From that hour, however, some distrust of the young man as an 'adventurer' took root and his subsequent career did too little to dispel it. It was not that Canning ever again changed his opinions or paltered with them for power. On the contrary, he remained a close follower of Pitt (except upon the point of Parliamentary Reform, to which he was always opposed and which Pitt himself now thought inexpedient), a free trader and a pro-Catholic all his life. That is to say, he was a sound Tory of the new school of Pitt. It was rather impatience for self-advancement and want of loyalty to colleagues of which he was, perhaps rightly, accused. On a man of such ambition, this was fearfully visited by his exclusion from office in the last critical years of the Napoleonic War.

He became one of the ablest, if not the most judicious, of Pitt’s colleagues, as Under-Secretary at the Foreign Office, in 1796. Pitt delighted in his wit, his scholarship, his readiness in debate and once even contributed to the brilliant political magazine the Anti-Jacobin, by which, in 1797-8, Canning, Ellis, Frere and Wellesley gave the Radicals a taste of what satire could be and got the laugh entirely on their side. A fortunate marriage with an heiress, in 1800, made Canning independent for life and gave him much domestic happiness. His wit and his warm affection also endeared him to a large circle of friends. In literature, if not an adherent of the Romantics, some of whom indeed were pilloried in the Anti-Jacobin, he admired Scott above all men and enjoyed his friendship to the end of his life. He was one of the projectors of the Quarterly Review in 1808. Meanwhile, in politics, he went out of office with Pitt, in 1801, and let fly the shafts of his wit against Addington, often to Pitt’s great discomfiture. In the latter’s second Ministry, Canning became Treasurer of the Navy in 1804. He was out during the Coalition of 1806, but became Foreign Secretary under Portland in 1807-9. During this period, he resided at South Hill Park in Easthampstead (Berkshire), where he planned the Seizure of the Danish Fleet, the saving of the Portuguese Fleet from the French and the Orders in Council and assented to the commencement of the Peninsular War. However, he both despised and was jealous of his own colleague, Castlereagh, head of the War Office, and, like himself, the pupil and political heir of Pitt. He was so anxious that no blame should attach to himself for any failures of the Government that he was ready to sacrifice the reputation of any subordinates or any colleagues, even that of Sir John Moore after Corunna. He was the warm friend of the Marquis Wellesley and was most anxious to attach the Wellesley brothers to himself and to draw them away from Castlereagh. He had not approved of, but he had not openly dissented from, the Walcheren Expedition in the Netherlands, for the failure of which, Castlereagh must bear a fair share. However, nothing can possibly excuse the intrigue that Canning then started, in Cabinet, against his colleague, who was kept, for months, in ignorance that his removal was being planned. When Castlereagh eventually discovered the intrigue, he challenged Canning to the famous duel which led to the resignation of them both. It looks very much as if Canning’s action had been prompted by the knowledge that Portland was failing in health and that either himself or Castlereagh would probably be his successor. When Perceval succeeded Portland, Canning refused to serve under him, and did his best to foment the impatience and jealousy of his friend Wellesley, who had taken the Foreign Office. When Liverpool came in and offered Canning that post, but rightly insisted that Castlereagh must lead the House of Commons, jealousy again prevented Canning’s acceptance. Thus, he stood aside during the triumphant conclusion of the War and only the favour of his old friend, Liverpool, procured him the brilliant post of Ambassador-Extraordinary in Lisbon to welcome the restored monarch of Portugal, who, after all, preferred to remain in the peaceful seclusion of Brazil. After Waterloo, Canning, who had recently been spending much time abroad, accepted the office of President of the India Board in 1816 and continued to support Liverpool’s Government until Queen Caroline’s trial in 1820. From some motive, now not easily discoverable, perhaps from mere lack of taste, he had allowed himself to be to some extent a friend of the unpleasant Caroline. The result was that when, after her death, he was willing again to join the Government, George IV was not so willing to have him as a Minister. In 1822, he had just accepted the Governor-Generalship of India, a post hereafter to be held illustriously by his nobler son, Charles; but, upon Castlereagh’s death, Liverpool felt strong enough to force Canning upon the King as Foreign Secretary.

The startling change that Canning inaugurated in British policy during his five years' tenure of this office (1822-7) built upon the foundations that Castlereagh had laid. Castlereagh did not make sparkling phrases about himself. However, the very words that Canning used about having "called the New World into existence to redress the balance of the Old" occur in stiff and ungainly prose in a dispatch of Castlereagh’s of 1822, in connection with the necessity of recognizing the independence of the revolted Spanish-American colonies. Just the same principles, for and against intervention in the concerns of foreign States, were followed and lucidly expounded by the orator Canning as had been followed, without exposition, by the dumb statesman, Castlereagh. The attitude of each to the policy of the ‘Holy Alliance’ was one of watchful mistrust. It suited Canning to pose as having had nothing to do with the settlement of the map of Europe in 1815, but it is greatly to his credit that, in practice, he did nothing to upset that settlement. Perhaps Castlereagh, who was the last man to be under illusions, might have displayed less interest than Canning displayed in the insurgent national movement of Greece. However, it is difficult to believe that he would have acted very differently from Canning towards Russia and Turkey, though it is probable that any action he might have taken would have been more successful.

When, in 1827, Liverpool, after fifteen years of admirably firm, wise and tactful government, for which history has never given him credit, was struck down by illness, George IV was confronted with the choice between Canning, with Catholic Emancipation, or Wellington and Peel, with the ‘Protestant Ascendancy’. It is difficult, considering the cause at stake, not to give one's sympathy, without reserve, to Canning. Here, as elsewhere, his principles were in the right, but now, as at other times, his method of getting himself into the position to carry out these principles exposed him to well-merited censure. The story is still obscure, but it looks very much as if Canning simply tricked the King into making him the Prmier against his, the King’s, real will. Greville's version (which came from Melbourne) was that "Canning said to the King, "Sir, your father broke the domination of the Whigs. I hope your Majesty will not endure that of the Tories" [ie. Peel and Wellington]. "No," said the King, "I’ll be damned if I do," and he made him [Prime] Minister." However, the result was that the Duke, Peel and their anti-Catholic friends resigned and Canning’s own Cabinet was obliged to include a few of the milder Whigs, as well as some sound free-traders from both parties. Indeed, it seems probable that, even before he had any communication with the King, perhaps even before Liverpool’s illness, Canning had been privately sounding out the Whigs as to their possible assistance. This had probably come to the ears of the Duke of Wellington who, not unnaturally, felt that no confidence could be placed in a man who would intrigue thus. Little space or scope, one hundred and twenty days only, were allowed the statesman to prove his mettle. Canning had caught a bad cold at the Duke of York’s funeral in January. He was ill during his whole tenure of the new office and he died in the August.

Canning lacked the serene temper which had made Pitt and Castlereagh able to bear storms far worse than any he had ever to face. Liverpool, who nevertheless loved him, used to complain of his fearful sensitiveness and irritability when attacked in the newspapers. His industry was immense and he possessed, beyond question, a mind to conceive and a heart to dare lightning strokes of policy, many of which were extremely successful. As a speaker he was always thinking too much of effect, especially of the effect the speech would have upon his own reputation, and too little of convincing his hearers, or telling the truth to the World. Not being quite a gentleman, he occasionally committed, in his speeches, appalling faults of taste and, in his actions, unpardonable breaches of honour.