John Kenneth Galbraith, seen in June 2001, advised Democratic presidents from Franklin D. Roosevelt and John F. Kennedy to Bill Clinton. (Harvard University News Office, Rose Lincoln/AP)

John Kenneth Galbraith – the Canadian-born Harvard professor who won worldwide renown as a liberal economist, backstage politician and witty chronicler of affluent society – died Saturday night at age 97.

Galbraith died of natural causes at Mount Auburn Hospital in Cambridge, Mass., where he was admitted two weeks ago, his son Alan said.

During a long career, the economist served as adviser to Democratic presidents from Franklin D. Roosevelt to Bill Clinton, and was John F. Kennedy's ambassador to India. "He had a wonderful and full life," his son told the Associated Press.

Galbraith was primarily seen as a U.S. economist, but he had a huge influence in Canada as well.

Stephen Clarkson, a University of Toronto economist, said Galbraith constantly argued for government intervention in the economy, theories that saw the light as greater investments in schools, Canada's system of farm safety nets and, most famously, the wage and price controls introduced in the 1970s by then-prime minister Pierre Trudeau.

Renowned for The Affluent Society

Galbraith was born Oct. 15, 1908, on a farm in Iona Station, Ont., just west of London. He went to Ontario Agricultural College, now the University of Guelph, before moving to the United States where he earned his PhD in economics from the University of California.

He taught at Harvard from 1934 to 1939 and at Princeton University from 1939 to 1942, then worked in the U.S. Office of Price Administration during the war years. Galbraith returned to Harvard in 1948, remaining active on the faculty until his retirement.

Galbraith was one of America's best-known liberals, a label that he seemed to like. He wrote forcefully and clearly on the need for government intervention in modern society.

One of his most influential books, The Affluent Society, was published in 1958.

It argued that the American economy was producing individual wealth but hasn't adequately addressed public needs such as schools and highways. Galbraith said U.S. economists and politicians were still using the assumptions of the world of the past, where scarcity and poverty were near universal.

In 1999, The Affluent Society was picked as No. 46 among the century's 100 best English-language works of non-fiction.

Galbraith tried 'to empower people directly'

"He's an amazingly imaginative and creative and hard-working person," fellow economist and longtime friend Paul Samuelson said in 1994. "There's no day that goes by that he doesn't write every morning, and it adds up to a lot."

Galbraith also was known for his theories on countervailing forces in the economy, arguing that groups such as labour unions were needed to strike a political and social balance.

Richard Neustadt, a Harvard colleague who also served as an aide to presidents Kennedy and Harry S. Truman, said Galbraith demonstrated how "you have to empower people directly before they could fight for themselves."

Galbraith's prose won admiration at the very top. When he was ambassador to India, Kennedy enjoyed his writing so much that he insisted on seeing all Galbraith's cables, "whether they were directed at the president or not," Neustadt said.

Hosted television program

After his retirement from Harvard in 1975, Galbraith gained fresh recognition as host of the British-made television series, The Age of Uncertainty. His book under the same title was a bestseller, as was Almost Everyone's Guide to Economics.

Among his other books were The Great Crash (1955) and The Culture of Contentment (1992). His 1996 book, The Good Society, outlined his blueprint for enriching America economically and socially, while his 1999 book, Name-Dropping: From FDR On, was a lighthearted look at his encounters with everyone from Eleanor Roosevelt onward.

"It is not usual for a man past his 90th birthday to write a book that is as fresh and lively as the work of a 30-year-old. But John Kenneth Galbraith is not a usual man, and he has done it," the New York Times wrote about Name-Dropping.

From Cambridge to Tokyo, the six-foot-seven Galbraith was an avid reciter of dry limericks and pungent, outrageous humour, often at the expense of American society.

Noting that by the law of aerodynamics, the bumblebee in principle cannot fly, Galbraith once remarked, "If all this be true, life among bumblebees must bear a remarkable resemblance to life in the United States."

Galbraith was married in 1937 to Catherine Atwater. They had three sons, Alan, Peter and James.