After college, Roach moved to San Francisco, California, and spent a few years working as a freelance copy editor.

Her writing career began in the public affairs office of the San Francisco Zoological Society, producing press releases on topics such as wart surgery on elephants.

[16] Roach reviews books for The New York Times and was the guest editor of the Best American Science and Nature Writing 2011 edition.

[18] She has been an Osher Fellow [19] at the San Francisco Exploratorium and has served on the Usage Panel of the American Heritage Dictionary.

[21] Stiff: The Curious Lives of Human Cadavers was a New York Times Bestseller, a 2003 Barnes & Noble "Discover Great New Writers" pick, and one of Entertainment Weekly's "Best Books of 2003."

[25] Gulp: Adventures on the Alimentary Canal was also a New York Times Bestseller and on the shortlist for the 2014 Royal Society Winton Prize for Science Books.

[26] Roach was the recipient of the Harvard Secular Society's Rushdie Award[27] in 2012 for her outstanding lifetime achievement in cultural humanism.