Eleanor Roosevelt was an immediate commercial success. The book was on the New York Times bestseller list for about three months and sold about 100,000 copies. It also won the Los Angeles Times Book Award.

While the book-buying public was enthusiastic, the response of critics and scholars was decidedly mixed. Cook's conclusions about Eleanor Roosevelt's private life proved controversial. Not only was the Roosevelt family angered, conservative critics also were aghast at Cook's argument that Roosevelt probably had an affair with her bodyguard, Earl Miller, and with her friend, the reporter Lorena Hickok. In a mocking article in National Review, Florence King made fun of many of Cook's premises, as in the following passage:

Lesbianism is often on the author's mind and she goes out of her way to find it, even hinting that Elliott Roosevelt's sister—ER's Aunt Corinne—had some sort of passionate interlude with...