After serving in the United States Army in War World I, he attended the Chicago Academy of Fine Arts.
William H Mosby was a professor of art at the American Academy of Art in Chicago, a painter, and illustrator. In 1924, he went to Europe and enrolled in the Royal Academy of Fine Arts in Belgium. In Europe, he learned classical technique which he later shared with his students at the American Academy of Art in Chicago.
He taught there from 1930 until his death in 1964 with the exception of a scholarship he was awarded at The National Higher Institute of Fine Arts in Antwerp, Belgium and to serve in the United States. Navy during World World War World War II An exceptional painter, he exhibited with the Art Institute of Chicago in 1934 and 1936.
He also did illustration work for such companies as Mars Candy, Goodrich Tires and Chrysler. Students Include: Richard Schmid, Gil Elvgren, Ted Smuskiewcz, Bill Parks, Howard Terpning, James J. Ingwersen and others