FOR MORE than half a century John Kenneth Galbraith was both Professor of Economics at Harvard University and a public intellectual, whose lucid writing expounded the Keynesian economics that he supported throughout his life. A product of New Deal America, he was John F. Kennedy’s Ambassador to India and adviser to Lyndon B. Johnson, but maintained that the great thrill of his life was debating with Friedrich von Hayek — and getting the better of him.

At 6ft 8in (2.03m) tall, Galbraith towered over his colleagues, and in his old age there was only a hint of a stoop. With his height came a confidence that stopped short of arrogance, but which was put to excellent use in the goodhumoured challenging of his fellow economists.

In a profession notorious for its descent into mathematical detail, the strength and clarity of Galbraith’s prose won him a wide and appreciative readership. He was not an innovator or theoretician in the sense that leads to the Nobel prize: his method was to sort out the wheat from the chaff of economic history and theory, and to popularise what emerged without lowering his intellectual standards.

His contribution was to apply fine judgment, experience and spirited writing to making the case for an intelligently run mixed economy. In the process, he produced devastating criticism of the ability of extreme market forces — or “the invisible hand” — to deliver the goods promised by the classical economists and their modern apostles, the propagators of Reaganomics and Thatcherism.

Coming from a Calvinistic, Scottish-Canadian background Galbraith was privately proud of the hard work and diligence which lay behind his public air of effortless superiority. He once said: “I put my manuscripts through the typewriter three times — first for sense, second for style, and third for both.”

Felicitious phrases were never wasted: by judicious repetition he worked them into the reader’s memory, and, indeed, into the language. The title of his most famous book, The Affluent Society (1958), is a household phrase, and it was in this bestseller that he coined the term “conventional wisdom” for “acceptable” ideas.

The book was going to be called The Opulent Society, but halfway through writing it, Galbraith realised that he could not stand the title and replaced it with the first word that he found in a thesaurus. The title The Affluent Society was also somewhat ironic, a prime example of Galbraith’s sardonic wit, for his point was that there had to be something wrong with a society, such as that in the US, in which there was so much “public squalor” amid the “private affluence”.

Keynes had said that there would be a time when society had to become accommodated to plenty rather than scarcity, and Galbraith said that this time had arrived. He went on to argue that rather than constantly creating material wants through advertising, the time had come to pay attention to the quality of life.

This led to his strong advocacy of a better balance between the public and private sectors — which he felt the classical economic model failed to achieve — and with his belief in the need for income redistribution, Galbraith was way out on the left of the American “liberal” wing in the 1950s. He summed up his theory when he testified against tax reduction before a congressional committee in 1965. “I am not quite sure what the advantage is in having a few more dollars to spend,” he said, “if the air is too dirty to breathe, the streets are filthy and the schools bad.” He had advised Kennedy against a major tax cut in the early 1960s — a cut that had inflationary consequences and which in some quarters gave his beloved “Keynesianism” a bad name.

Galbraith had already earned his spurs as an expert on American capitalism with American Capitalism — the Concept of Countervailing Power (1952), which explained how the real industrial and commercial world was far removed from the perfect, “atomistic” competition envisaged by classical economists, and with The Great Crash 1929 (1955). The latter is one of the most easily digestible books on the financial markets ever written, and no one who has read it could be left in any doubt of Galbraith‘s views on the fallibility of markets.

It was in The New Industrial State (1967) — considered by many to be his greatest book — that Galbraith’s analysis of modern corporate America was perfected. “Planning” might be a dirty word in the United States, but it was at the heart of what big corporations did. Often helped by government sponsorship or procurement, the “technostructure” that ran big business was responsible for most of the useful research, and at the heart of the process of technological change.

The seeds of this expertise in modern industrial capitalism had grown out of a very agricultural background. John Kenneth Galbraith — later in life he preferred to be called Ken — was born in 1908 and brought up on a small farm in Ontario, near Lake Erie and the US border. It was Canada’s bad luck that most of the world thought of him as an American.

He was the son of a local Liberal Party leader and schoolteacher turned farmer who also stood at 6ft 8in. The young Galbraith graduated in agriculture at the Ontario Agricultural College in the town of Guelph where he learnt cheesemaking, butchering and soil management. He only moved on to mainstream economics at the universities of Berkeley, California, and Cambridge, England.

Galbraith became an American citizen in 1939 and began to teach economics at Princeton. During the war he worked in the Office of Price Administration but by 1943, he wrote, “I reached the point that all price fixers reach. My enemies outnumbered my friends.”

Rejected by the army as being too tall, he then held a variety of jobs, including the directorship of the US Strategic Bombing Survey which investigated the economic impact of the Allied bombing of Germany and required the interrogation of Nazi leaders.

In 1948 he became Professor of Economics at Harvard and began to spark a fierce debate about the role of government in the economy. Much of his academic career was spent at Harvard, the family house being in Cambridge, Massachusetts. It was here that he met Kennedy, whom he taught, and his future wife, Kitty, who was studying comparative literature at Radcliffe, at that time Harvard’s affiliated college for women. “My wife has had far more responsibility for the children than I have,” Galbraith said later in life. “But I am a better writer than she is.”

In 1937, the day after their marriage, they sailed to England, and it was in Cambridge that Galbraith briefly sat at the feet of J. M. Keynes, having been devoted to the great man since reading The Economic Consequences of the Peace. Galbraith returned to Cambridge as a Fellow in 1970.

He was an Anglophile, and enjoyed reading Trollope and Austen. His love of this country was returned by the great recognition shown here towards his work, and in 1966 he was invited to give the Reith lectures, in which he stated the necessity for economic planning. With his wife he regularly passed through London, often en route to their chalet in Gstaad, where for many years he enjoyed skiing and found the mountain atmosphere highly conducive to creativity. They also had a more accessible 247-acre farm retreat in Vermont.

But despite his penchant for planning and public intervention, he was a liberal and a Democrat, with no illusions about socialism. For Galbraith “socialism existed in superbly attractive form in oratory, in literature and in belief, but it was not a viable design”. Nevertheless, Galbraith confessed that he was disappointed at the collapse of communism, and took mischievous pleasure in being one of the few Westerners to be honoured by the Soviet Academy of Sciences.

Galbraith was close to the Kennedy family, and is said to have written the famous lines in Kennedy’s inaugural address: “Let us never negotiate out of fear. But let us never fear to negotiate.”

Kennedy wanted “a man I know” to deal with Nehru, forcing Galbraith to leave a half-written book in America in a bank vault. Despite his penchant for active government, he admired the way that the Raj was run with so few civil servants — as he was fond of saying, “with fewer people than Harvard employs in its dining halls” — but he remained in Delhi for only two years. Kennedy liked his reports so much that he demanded to see them even if they were addressed to someone else, but Galbraith wanted to return to Harvard in order to preserve his tenure, and did so in 1963, saying that he was “a one-time-only diplomat”. In 2001 he received India’s second highest civilian award, the Padma Vibhushan, and although he was too frail to get to his feet to accept the honour, he said: “Nothing gives me greater pride than looking back on my two excursions to what we shall one day call the world’s most successful democracy.”

He packed a lot into his two ambassadorial years, subsequently producing Ambassador’s Journal, a book entitled Indian Painting (1973), The Nature of Mass Poverty and a satire on diplomacy, The Triumph, under the pseudonym Mark Epernay. He had found that ambassadors had to listen to interminable speeches and that “it was rude to read during these speeches, but I could do a lot of writing. People thought one was taking notes.”

In 1968 he joined the Eugene McCarthy peace campaign and it was typical of what some might have called his pride — but to his friends was something more like self-respect — that he resolutely refused to desert it once Robert Kennedy made his belated entrance into that year’s presidential race. Whatever his affection for the Kennedy family, he was never a mere courtier of Camelot.

To Galbraith, the Vietnam War was one that “we cannot win, and one we should not wish to win”. He had vehemently advised Kennedy against it in private. But after Galbraith declared his opposition in public, Johnson never spoke to him again; previously he had been influential in Johnson’s Great Society domestic policies.

He was no fan of Richard Nixon, of whom he said: “I never met him, but apparently he worked for me during the war.”

He once claimed that his star had been fading in the late 1970s until The Observer asked him to write an article about Milton Friedman and the Thatcher Government’s embrace of monetarism. The article was syndicated worldwide, and, according to Galbraith himself, put him “back on the map”. His one reverse in Britain had been a 13-part series about modern industrial society for the BBC in 1977 called The Age of Uncertainty, which cost £1 million and took two and a half years to make, but could not claim to repeat the success of Jacob Bronowski’s The Ascent of Man and Kenneth Clark’s Civilisation.

In the 1980s and 1990s, easily understandable yet economically sound books continued to flow from his pen in rapid succession, including The Culture of Contentment (1992), in which, saddened by the anti-welfare turn that even the Democrats had taken in the United States, he suggested that there was no longer a large enough political constituency for the poor. He said that the culture of contentment was conducive to the public squalor and private affluence that he had analysed over three decades previously in The Affluent Society, and explained the victory of the Conservative Party in Britain in the same year.

In his last major work, The Great Society (1997), Galbraith gave his definition of the perfect political system. The rich accepted high rates of taxation, immigrants were welcomed and education was seen as important as an end in itself. Happiness, he said, did not require an expanding economy.

He counted a number of British public figures among his friends — including John Freeman, Nicholas Henderson and, in years gone by, Richard Crossman, R. A. Butler (to the American edition of whose autobiography, The Art of the Possible, he wrote the introduction), and Roy Jenkins, who said that Galbraith’s home should be transported to the Smithsonian Institution and exhibited as the habitat of the American academic in the second half of the 20th century.

Galbraith regretted not being more active in electoral politics. He had pulled out of running for the Senate on the eve of an election because he realised that winning would mean removing a black man from the House, and pulled out on a different occasion because he was in the middle of writing a book. He also wished that at an earlier age he had started writing novels.

He once told the oral historian Studs Terkel: “I do a lot of my reading not for the sake of information but because it is a bridge over idleness. Idleness is the one thing I can’t live with.”

Though visibly frail towards the end — “I won’t get up”, he would bellow to visitors, “those days are gone” — he maintained an active interest in public affairs. He opposed the invasion of Iraq, and was both mystified and saddened by the Blair Government’s support for George W. Bush.

The most famous and best-selling economist in the world, Galbraith published the last of more than 40 books — The Economics of Innocent Fraud in 2004 — in his 96th year.

He is survived by his wife Kitty (Catherine Merriam Atwater), whom he married in 1937, and three of their four sons (one son died in childhood).

John Kenneth Galbraith, economist, was born on October 15, 1908. He died on April 29, 2006, aged 97.