At seventeen Fields traveled from his home in Portsmouth, New Hampshire, to Boston, where he apprenticed at the Old Corner Bookstore and began writing for newspapers. After he was invited to join a major publishing firm, it soon became known as Ticknor and Fields, and now James T. Fields is celebrated in American National Biography as the foremost publisher of the literature in mid-nineteenth century America. He succeeded James Russell Lowell as editor of the Atlantic Monthly.

Fields not only published eminent authors but frequently established intimate relations with them. Among his authors of English literature were Charles Dickens, George Eliot, Alfred Tennyson, and Thomas De Quincy (twenty-three volumes). The American authors of acquaintance included Hawthorne and Holmes, Emerson and Whittier, Harriet Beecher Stowe and Bret Harte, whom he brought east from California.