William Wilson Cowell was born in Boston, Massachusetts, the son of William Cowell and well-known, popular Chicago actress, Anna Cruise Cowell. Cowell studied at the Pennsylvania Academy of the Fine Arts with marine painters, Edward Moran and John Faulkner. He painted in New York State, notably the Adirondack Mountains and the Hudson River, Newport and the Narragansett Bay, Rhode Island, the rocky coasts of Hahant and Marblehead, Massachusetts and the Bay of Fundy, Nova Scotia.

Circa 1895, Cowell moved to Chicago, Illinois, but spent his summers in Nova Scotia. He adopted a primarily luminist manner in his landscapes and marine scenes; however, although many of paintings are of ships at sunset or at night, they maintain the characteristic low horizon of the luminists, with the diffused light of the setting sun or rising moon. Cowell was a member of the Brooklyn Art Association and the National Academy of Design, where he also exhibited. He also exhibited at the Pennsylvania Academy of the Fines Arts from 1876 to 1900 and the Art Institute of Chicago.