A Chicago chef known for his ethereal cooking — as well as the tongue cancer that nearly ended his life — was named the nation’s top chef Sunday by the James Beard Foundation.

The award marked another victory in a tumultuous year for Grant Achatz, who last July was diagnosed with stage four tongue cancer, underwent aggressive treatment to save his life and sense of taste, and by December was cancer-free.

Mr. Achatz’s cooking at his three-year-old restaurant, Alinea, has come to define the so-called molecular gastronomy movement, an approach to eating about as similar to home cooking as particle physics is to a junior chemistry set.

His ultramodern style has crafted menus that read like the shopping list of a culinary mad scientist, with items such as “black truffle explosion, romaine, parmesan” and “transparency of raspberry, rose petal, yogurt.”

Alinea was named the nation’s top restaurant by Gourmet magazine in 2006, and Mr. Achatz previously won Beard awards for rising star chef in 2002 and 2003, and for best chef in the Great Lakes region last year.

The James Beard awards are known as the Oscars of the food world, and honor those who follow in the footsteps of Beard, considered the dean of American cooking when he died in 1985.

Business partners Mario Batali and Joe Bastianich also were honored at Sunday’s ceremony as the nation’s top restaurateurs. They oversee a cadre of restaurants, including New York’s Babbo Ristorante e Enoteca and Del Posto.

New York’s Gramercy Tavern was named the nation’s Outstanding Restaurant.