Fallows was born and raised in Redlands, California. He studied American history and literature at Harvard University, where he was the editor of the daily newspaper, the Harvard Crimson.
From 1970 to 1972 Fallows studied economics at Oxford as a Rhodes scholar. He subsequently worked as an editor and writer for the Washington Monthly and Texas Monthly magazines.
For the first two years of the Carter administration he was Carter's chief speechwriter.
From 1979 through 1996, Fallows was the Washington Editor for The Atlantic Monthly. For two years of that time. he was based in Texas, and for four years in Asia. He wrote for the magazine about immigration, defense policy, politics, economics, computer technology, and other subjects.
While at The Atlantic Monthly, he published five books: National Defense (1981), More Like Us (1989), Looking at the Sun (1994), Breaking the News (1996), and Free Flight: Inventing the Future of Travel (2001).
In the 1980s and 1990s Fallows was a frequent contributor of commentaries to NPR's Morning Edition.
From 1996 to 1998, he was the editor of US News & World Report.
Fallow's have appeared in Slate, The New York Times Magazine, The New York Review of Books, The New Yorker, The American Prospect, and other magazines.
Since 1998, he has been chairman of the board of the New America Foundation, a nonprofit group based in Washington D.C
During the first six months of 1999, Fallows worked at Microsoft designing software for writers.
During the 2001 – 2002 academic year, Fallows taught at the graduate school of journalism at the University of California, Berkeley.