Upon returning to Cincinnati after their Honeymoon, was hired as an illustrator for the advertising art firm C.H. Schaten Studios, later LPK. Proctor& Gamble was headquartered in Cincinnati making the city a hub for advertising and printing, but he was dissatisfied with the commercial art world. Ford Times Magazine began commissioning his work in 1948 and provided Harper with a national audience for his animals and landscapes. Published by the Ford Motor Company, it included articles by literary greats such as John Steinbeck and E.B. White and was distributed in Ford dealerships to promote brand loyalty and travel. His illustrations encouraged readers to visit national landmarks and explore the diversity of nature. His first Ford Times cover in April 1951 which featured five fish swimming amongst hooks received an overwhelming response, prompting the magazine to begin offering screen prints, also called serigraphs by mail order. Harper contributed to at least 120 Ford Times publications from April, 1948 up until June of 1982.