Born in New Bedford, Massachusetts, Clifford Ashley received his initial training at Boston's Eric Pape School. In 1901, he studied with Boston Impressionist George Noyes. Shortly thereafter, he began his studies with Howard Pyle in Wilmington, DE, where he established a studio. In 1904, he spent 6 weeks on a whaling trip (in the final years of American whaling fleets). After 1904, he often spent some parts of the year in Wilmington and others in New Bedford (the historical center of American whaling), and on his family farm in Westport, Massachusetts. In 1916 his moved his permanent Massachusetts residence to Fairhaven. After his marriage in 1932 to Sarah Rodman Scudder Clark, the couple lived in Westport, Massachusetts. They had two daughters.
Although Ashley illustrated a range of subjects, he became known as a specialist in marine illustration. Most particularly, he wrote and illustrated whaling-related books and magazine articles. Two of his major contributions to historical whaling literature were Whaleships of New Bedford,1929, and The Ashley Book of Knots, 1944. The latter features drawings of whaling scenes and knot-making; Ashley invented many of its approximately 3900 different types of knots. He learned knot-making as a child from two uncles who were whaling captains.
During World War I, Ashley was one of over fifteen hundred American artists who produced posters for the United States Division of Pictorial Publicity on behalf of the war effort.
Ashley died in Westport Point, Massachusetts.
In 1973, the New Bedford Whaling Museum, in conjunction with the Brandywine Museum, mounted a major show of Ashley's work.
Sources:
http://www.schoonoverstudios.com/howard-pyle-a-students/pyle-students-bios/11-ashley-clifford-warren-1881-1947.html
https://timesmachine.nytimes.com/timesmachine/1947/09/20/87817757.html?pageNumber=14