Charles J. Shields was born in Chester, Pennsylvania on the Delaware River but raised in Park Forest, Illinois, a community for veterans and their families, an experiment in post-war planning described and critiqued in William H. Whyte's The Organization Man. Shields later attended the University of Illinois, Champaign-Urbana, where he received degrees in English and American history.

Shields published his first biography for adults in 2006, and Mockingbird: A Portrait of Harper Lee went on to became a New York Times bestseller. "This biography will not disappoint those who loved the novel and the feisty, independent, fiercely loyal Scout, in whom Harper Lee put so much of herself," wrote Garrison Keillor in the New York Times Sunday Book Review. "As readable, convincing, and engrossing as Lee's literary wonder," said the Orlando Sentinel.

Two years later, Shields followed-up his biography of Lee with a young adult version: I Am Scout: The Biography of Harper Lee, which received awards from American Library Association Best Books for Young Adults; Bank Street Best Children's Book of the Year; Arizona Grand Canyon Young Readers Master List.

In 2009, with fellow biographers Nigel Hamilton, James McGrath Morris, and Debby Applegate, Shields co-founded Biographers International Organization (BIO), a non-profit organization founded to promote the art and craft of biography, and to further the professional interests of its practitioners. As of July 2011, BIO has members in 43 American states and 10 nations, including Australia, India, Kenya, and the Netherlands.

Shields is also associate director of the Great Lives Lecture Series at the University of Mary Washington in Fredericksburg, Virginia which brings prominent biographers and historians to campus. In November 2011, Shields published the first biography of Kurt Vonnegut, And So It Goes: Kurt Vonnegut, A Life.