Boston ? John Kenneth Galbraith, the Harvard professor who won worldwide renown as a liberal economist, backstage politician and witty chronicler of affluent society, died Saturday night, his son said. He was 97.

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

During a long career, the Canadian-born 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 said.

Galbraith, who was outspoken in his support of government action to solve social problems, became a large figure on the American scene in the decades after World War II.

He was one of America’s best-known liberals, and he never shied away from the label.

“There is no hope for liberals if they seek only to imitate conservatives, and no function either,” Galbraith wrote in a 1992 article in Modern Maturity, a publication of the American Association of Retired Persons.

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

In 1999, a panel of judges organized by the Modern Library, a book publisher, picked “The Affluent Society” as No. 46 on its list of the century’s 100 best English-language works of nonfiction.

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 best-seller, as was “Almost Everyone’s Guide to Economics.”

Among his other books were “The Great Crash,” 1955, and “The Culture of Contentment,” 1992. He returned to the theme of the crash of 1929 in a January 1987 Atlantic Monthly article that correctly predicted that year’s market plunge by citing the parallels of the two eras.

Galbraith was born Oct. 15, 1908, in Iona Station, Ontario, Canada.

After graduating from the University of Toronto in 1931, Galbraith moved to the United States where he earned his Ph.D. 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 federal Office of Price Administration during the war years.

Galbraith returned to Harvard in 1948, remaining active on the faculty until his retirement.

He was the recipient of the Medal of Freedom, awarded by Truman in 1946, and another one from President Clinton in 2000. The professor also served as president for a term of the American Economic Assn.

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