In general, The Known World was lauded as an extraordinary novel when published in 2003. Critics praised Jones's subject matter and the way in which he handled it, as well as his characterizations, prose, and the way he paced and constructed the story. Calling the novel "the best new work of American fiction to cross my desk in years," Jonathan Yardley of the Washington Post went on to state, "The Known World ventures into previously uncovered places and shines a light on them that is at once blindingly bright and surpassingly warm."

A number of critics admired how Jones drew his characters and interlinked their stories. For example, Conger Beasley, Jr., of the National Catholic Reporter commented, "where Jones really succeeds is in the depiction of character, the interaction between the myriad figures—black-white, black-black, white-white—who populate this excruciating world." Writing in the Black Issues Book...