After farming in Canada, operating a hotel, mining in the Alaskan goldfields, and working as a newspaper reporter in New York City, experiences that he recalled in Episodes Before Thirty (1923), Blackwood returned to England in 1899. Seven years later he published his first book of short stories, The Empty House (1906), and became a full-time fiction writer. Later collections include John Silence (1908), stories about a detective sensitive to extrasensory phenomena, and Tales of the Uncanny and Supernatural (1949), 22 stories selected from his nine other books of short stories.

In his later years Blackwood achieved a wide audience as a teller of ghost tales on British radio and television.