From June 1992 to September 1996, Kluger was a staff writer for Discover magazine, writing the humor column "Light Elements". He also worked as a writer and editor for the New York Times Business World Magazine, the Family Circle magazine, and Science Digest.

Kluger began his work with TIME in 1996 specializing in science coverage. He was named a senior writer in 1998. During his time at TIME magazine Kluger has written articles covering the Mars Pathfinder landing and the Columbia disaster.

Kluger was awarded the Whitman Bassow Award by the Overseas Press Club of America in 2002, an award he shared with two other colleagues. The award was given for "best reporting in any medium" on the international issues of global warming.

Kluger has most notably authored The Perilous Voyage of Apollo 13, published October 1994, which was coauthored with Jim Lovell. Lost Moon would become the basis for the Ron Howard film Apollo 13 starring Tom Hanks. Kluger would later be a technical consultant for, and appear in the movie Apollo 13: The IMAX Experience. He also authored a number of books about the space program including:

• The Apollo Adventure: The Making of Apollo Space Program and the Movie Apollo 13, July 1995, foreword by director Ron Howard. ISBN 978-0671535421
• Journey Beyond Selene: Remarkable Expeditions Past Our Moon and to the Ends of the Solar System, published July 1999, ISBN 0684847655
• Moon Hunters: NASA's Remarkable Expeditions to the Ends of the Solar Systems, published July 2001, ISBN 978-0684865591

Other topics Kluger has written about include:

• Splendid Solution: Jonas Salk and the Conquest of Polio, published January 2005, ISBN 978-0399152160, a book about the development of the polio vaccine.
• Nacky Patcher & the Curse of the Dry-Land Boats, a children's book, illustrated by David Elliot, June 2007. ISBN 978-0399246043.
• Simplexity: Why Simple Things Become Complex (and How Complex Things Can be Made Simple), June 2008, ISBN 978-1-4013-0301-3

Kluger attended Pikesville High School in Pikesville, Maryland, a northwest suburb of Baltimore. He is a licensed attorney, having earned a Juris Doctor from the University of Baltimore School of Law. He has taught journalism at New York University.