Grossman has written for The New York Times, Salon.com, Lingua Franca, Entertainment Weekly, Time Out New York, The Wall Street Journal, and The Village Voice. He has served as a member of the board of directors of the National Book Critics Circle and as the chair of the Fiction Awards Panel.

In writing for Time, he has also covered the consumer electronics industry, reporting on video games, blogs, viral videos and Web comics like Penny Arcade and Achewood. In 2006, he traveled to Japan to cover the unveiling of the Wii console. He has interviewed Bill Gates, Steve Jobs, Salman Rushdie, Neil Gaiman, Joan Didion, Jonathan Franzen, J.K. Rowling, and Johnny Cash. He wrote one of the earliest pieces on Stephenie Meyer's Twilight series. A piece written by Grossman on the game Halo 3 was criticized for casting gamers in an "unfavorable light." Time Magazine Takes Shots at Gamers with Halo 3 Article

In response to his novel Warp receiving largely negative customer reviews, he submitted fake reviews to Amazon using false names. He then recounted these actions in an essay titled "Terrors of the Amazon".

Grossman is the twin brother of video game designer and novelist Austin Grossman, and brother of sculptor Bathsheba Grossman. He is an alumnus of Lexington High School and Harvard College. Grossman attended a Ph.D. program in comparative literature for three years at Yale University, but left before completing his dissertation. He lives in Brooklyn with a daughter named Lily from a previous marriage and his second wife, Sophie Gee, whom he married in early 2010.

Grossman’s New York Times bestseller The Magicians was published in hardcover in August 2009 by Viking/Penguin. The Plume/Penguin paperback edition was made available on May 25, 2010. The Washington Post called it “Exuberant and inventive...Fresh and compelling...a great fairy tale.” The New York Times said the book "could crudely be labeled a Harry Potter for adults," injecting mature themes into fantasy literature.

The Magicians is a contemporary dark fantasy about Quentin Coldwater, an unusually gifted young man who obsesses over Fillory, the magical land of his favorite childhood books. Unexpectedly admitted to Brakebills, a very secret, very exclusive college of magic in upstate New York (an amalgam of Bannerman's Castle and Olana), Quentin receives a thorough and rigorous education in the craft of modern sorcery. After graduation, he and his friends make a stunning discovery: Fillory is real. But the land of Quentin’s fantasies turns out to be much darker and more dangerous than he could have imagined. His childhood dream becomes a nightmare with a shocking truth at its heart. [1]

The Magicians is also a 2010 Alex Award winner, given to ten adult books that are appealing to young adults.