Ruhlman grew up in Cleveland and was educated at University School, a private boys' day school in Cleveland's suburbs, and at Duke University, from which he graduated in 1985.

Ruhlman worked a series of odd jobs (including a brief stint at The New York Times) and traveled before returning to his hometown in 1991, to work for a local magazine.

While working at the magazine, Ruhlman wrote an article about his old high school and its new headmaster, which he expanded into his first book, Boys Themselves: A Return to Single-Sex Education (1996).

For his second book, The Making of a Chef (1997), Ruhlman enrolled in the Culinary Institute of America, taking a variety of classes but not graduating, to produce a first-person account...of the techniques, personalities, and mindsets...of culinary education at the prestigious chef's school. The success of this book produced two follow-ups, The Soul of a Chef (2000) and The Reach of a Chef (2006).

Ruhlman has also collaborated with chef Thomas Keller to produce the cookbooks The French Laundry Cookbook (1999), Bouchon (2004), Under Pressure (2008), and Ad Hoc At Home (2009); with French chef Eric Ripert and Colombian artist Valentino Cortazar to produce the lavish coffee-table book A Return to Cooking (2002); and with Michigan chef Brian Polcyn to produce Charcuterie: The Craft of Salting, Smoking and Curing (2005). In 2009 Ruhlman also collaborated with fellow Clevelander and Iron Chef Michael Symon on Symon's first cookbook Live to Cook.

In 2007, he produced "The Elements of Cooking" based on the structure of the classic grammar book "The Elements of Style." The book included essays about the importance of fundamentals in cooking such as heat, salt and stock, along with a reference guide to cooking terms. Much of the insight in the book is based on his previous food-related experiences at the Culinary Institute of America and from working with celebrity chefs.

In 2009, he published "Ratio: The Simple Codes Behind the Craft of Everyday Cooking," a book that explores basic preparations...bread, pie dough, custards...and how knowing the proportions of the ingredients by weight can free you from a subservience to recipes. He also made it available in full as an iPhone application.

Television

Ruhlman has acted as a judge on the PBS reality show Cooking Under Fire and on The Next Iron Chef. He has also made several appearances in shows hosted by Anthony Bourdain. In Bourdain's A Cook's Tour he joined Bourdain and Eric Ripert for a meal at Thomas Keller's The French Laundry restaurant. In No Reservations he appeared in three episodes, one devoted to Las Vegas, one devoted to Ruhlman's native Cleveland, and one devoted to New York's Hudson Valley.