Smedley was one of the most popular American illustrators of the nineteenth century. His father, a miller and Quaker minister, sent fifteen-year-old William to work for the Daily Local News in Westchester, Pennsylvania. The editor of the paper encouraged him to move to Philadelphia to study with Thomas Eakins at the Pennsylvania Academy of the Fine Arts. He then toured the South Seas before studying in Paris under Jean-Paul Laurens. In the early 1880s, Smedley moved to New York, where his illustrations began appearing in popular magazines. In 1882, he accompanied the Marquess of Lorne, a son-in-law of Queen Victoria who had recently been appointed Governor General, on his tour of Canada. He drew and sketched, preparing illustrations for ‘Picturesque Canada’. He went to Australia in the mid-1880s to work on a commission for Scribner’s Magazine, and took advantage of his time abroad to travel to India and work in Paris for a time. Smedley returned to New York, where his illustrations sold for top prices, but in the early twentieth century he decided to focus on portraiture. (Pensler, The Illustrations of W.T. Smedley, 1981)

He was a member of the Society of American Artists and a member of the National Academy of Design in 1905. His work is represented in the permanent collections of the Smithsonian American Art Museum, the American National Gallery of Art and the Art Gallery of New South Wales.

Most of his work was magazine and book illustration for stories of modern life, but he painted portraits and watercolours, and received the Evans Prize of the American Watercolour Society in 1890, and a bronze medal at the Paris Exposition of 1900.