James Geary is an adjunct lecturer in public policy at the Harvard Kennedy School, a lecturer in journalism at Brandeis University, and a lecturer in the English and Journalism departments at Boston University. He has also taught at Bennington College, Tufts University and the Harvard Extension School. From 2013 to 2023, he was the deputy curator of the Nieman Foundation for Journalism at Harvard and editor of Nieman Reports. He is the former editor of the European edition of Time magazine. He is the author of Wit's End: What Wit Is, How It Works, and Why We Need It,  I Is an Other: The Secret Life of Metaphor and How It Shapes the Way We See the World, Geary's Guide to the World's Great Aphorists, the New York Times bestseller The World in a Phrase: A Brief History of the Aphorism, and The Body Electric: An Anatomy of The New Bionic Senses.

Geary has performed, given talks and / or conducted writing workshops at, among other venues, TED, Live from the New York Public Library, the Bread Loaf Writer's Conference, the Sun Valley Writer’s Conference, the Edinburgh Book Festival, the Hay-on-Wye Festival, the Genoa Science Festival, the Chautauqua Institution and the Seoul Digital Forum.