John Kenneth Galbraith stands almost seven feet tall, but that’s not the only thing that makes him a big man. He seems omnipresent in American history of the last half-century. Imagine Forrest Gump with a Ph.D., and you’ll have a good idea of Galbraith’s life as famous economist, counselor to presidents, diplomat, and best-selling author. Sadly, few economists pay attention to his work today, largely because Galbraith is a moralist in a profession dominated by objectivity and statistics. Richard Parker, an instructor at the Ken­nedy School of Government at Harvard University, has come to the rescue with a biography equal to Galbraith’s stature.

Born in rural Canada in 1908, Galbraith studied at Ontario Agricultural College and then at the University of California, Berkeley, abandoned agricultural economics for Keynesian macroeconomics, and served his adopted country during World War II—most importantly in the Office of Price Administration. Along the way, he developed a “talent for making friends with wealthy and powerful people” while remaining independent and strongly committed to liberal principles. Beginning in 1943, he spent five years writing for Fortune magazine; it was conservative Henry Luce, ironically, who enabled him to hone his journalism skills.

After struggling for tenure at Harvard (it was finally granted in 1949), Galbraith could have settled down to a comfortable academic life. Instead, he advised Adlai Stevenson and then John F. Kennedy, and, through the Kennedy connection, was appointed ambassador to India in 1961. Though serving as a diplomat, Galbraith remained a critic, even of his own boss’s foreign policy toward Cuba and Vietnam.

During this busy life, Galbraith wrote about economics for a wide audience, most famously in The Affluent Society  (1958), a book that lambasted America’s “social imbalance” between private consumption and public goods. Remarkably, his status as a best-selling popularizer of economics didn’t keep Galbraith from ascending to the presidency of the American Economic Association in 1972.

Parker recounts the details and does even better at supplying  context. In the latter portion of the book, Galbraith’s influence wanes as Amer­ican politics drifts rightward; none­theless, the biographer provides especially informative ac­counts of the 1970s and of economic policy un­der Presidents Ronald Reagan and Bill Clinton.

Broad themes emerge, including Galbraith’s struggles between careerism and a love of big ideas, and between sticking to principle and exerting influence in the gritty world of politics. Discussing his legacy, Parker sensibly suggests that economists should strive to write for a wider public. Less sensible is the author’s optimism about the staying power of Galbraith’s brand of liberalism.

Another shortcoming: Parker often piles detail upon detail and then squeezes in a footnote for another anecdote. Sometimes, too, he apologizes for mentioning something that’s “slightly ahead of our story” or that lies “in the future.” In an 800-page book, these practices get wearisome. Nonetheless, those who make it through will come away with a true appreciation of John Kenneth Galbraith’s contributions, especially the questions he asked about the moral underpinnings of modern capitalism.

—Kevin Mattson