Xanthus Russell Smith was an American marine painter best known for his illustrations of the American Civil War.

Born in Philadelphia, Pennsylvania, the son of painters William Thompson Russell Smith and Mary Priscilla Wilson, he was educated at home by his mother, who also gave him drawing lessons. Between 1851 and 1852, he accompanied his parents and sister Mary Russell Smith on the family's tour of Europe. After returning home, he studied chemistry at the University of Pennsylvania, before enrolling at the Pennsylvania Academy of the Fine Arts. He served in the Union Navy as a captain’s clerk during the American Civil War, helping to maintain the blockade of Charleston, South Carolina. He saw little action, and sketched hundreds of ships in a variety of media, including pencil and oil paint, both for official purposes and for his own pleasure.

His father built a suburban villa, "Edgehill", in Glenside, Pennsylvania, a couple miles outside of Philadelphia, that included a large artist's studio. In 1879, Smith married Mary Binder, the daughter of a wealthy Philadelphia lumber dealer. The Smiths settled at Edgehill, where they raised their three children, Mary Russell "Polly" (1880–1938), Xanthus Russell Jr. (1886–1961), and George Russell (1890–1943). Smith also maintained a studio at 1020 Chestnut Street in Philadelphia for over thirty years, and painted until his death at age 90.