[2] Grosvenor subsequently worked as a freelance photographer, completing 23 assignments for the magazine and its book division in such countries as Belize, France, Iceland, Spain, Tonga, and Turkey.

[7][8] "Since no magazine was going to hire a 27-year-old to be editor in chief, the only solution was to start my own," he told a reporter for the Palm Beach Post.

It published an eclectic mix of writing by such authors as Martin Amis, E.L. Doctorow, Henry Louis Gates, Jr., Jane Goodall, Stephen Hawking, Richard Leakey, John McPhee, Bill Moyers, Joyce Carol Oates, George Plimpton, Salman Rushdie, and John Updike.

In 2012 and 2013, Grosvenor led a team developing Fourscore (4score.org), an educational website offering thousands of essays and documents for teaching American history and government.

[16] Although American Heritage was forced to stop print publication in 2012, Grosvenor led a group of volunteers that relaunched a digital version of the magazine in June 2017.

[17] Grosvenor is the author, with Morgan Wesson, of Alexander Graham Bell: The Life and Times of the Man Who Invented the Telephone (Harry N Abrams, 1997),[18] a biography of his great-grandfather.