Powell was born and raised in Austin, Texas. She graduated from Amherst College in 1995 with a double major in theater and creative writing. She later married Eric Powell, an editor for the magazine Archaeology.

While working for the Lower Manhattan Development Corporation in August 2002, Powell began the Julie/Julia Project, a blog chronicling her attempt to cook all the recipes in Julia Child’s Mastering the Art of French Cooking. The blog quickly gained a large following, and Powell signed a book deal with Little, Brown and Company. The resulting book, Julie and Julia: 365 Days, 524 Recipes, 1 Tiny Apartment Kitchen, was published in 2005. The paperback edition was retitled Julie and Julia: My Year of Cooking Dangerously.

In 2009, Powell was awarded an honorary diploma from Le Cordon Bleu, the same cooking school from which Child graduated in 1951.