American short story writer and novelist, was born the son of Andrew Robertson, a ship captain on the Great Lakes, and Amelia (Glassford) Robertson. Morgan went to sea as a cabin boy and was in the merchant service from 1866 to 1877, rising to first mate. Tiring of life at sea, he studied jewelry making at Cooper Union in New York City and worked for 10 years as a diamond setter. When that work began to impair his vision, he turned to writing sea stories, placing his work in such popular magazines as McClure's and the Saturday Evening Post. Robertson never made much money from his writing, a circumstance that greatly embittered him. Nevertheless, from the early 1890s until his death in 1915 he supported himself as a writer and enjoyed the company of artists and writers in a small circle of New York's bohemia. Robertson was found dead of heart disease in an Atlantic City hotel room.