A prolific magazine illustrator in the Norman Rockwell vein, Mingo resided in the Chicago area for numerous decades before latterly retiring to Tarrytown, New York. In his pre-Mad years, he worked as an illustrator for various advertising agencies and magazines, including American Weekly, Ladies' Home Journal and Pictorial Review. He provided a bikinied pin-up girl for a 1946 Mennen Skin Bracer advert, signed with his distinctive Mingo script. In addition to pin-up art, he also illustrated for paperbacks (Pocket Books) and paper dolls (Deanna Durbin).
In 1956 Mingo answered a New York Times ad for an illustrator, and was selected by Mad publisher William M. Gaines and editor Al Feldstein to create a warmer, more polished version of a public domain character the magazine had been using. Previously, the magazine had printed a rougher image and redrawings of the character, which were randomly dubbed "Melvin F. Coznowski" or "Mel Haney" in addition to "Alfred E. Neuman." The pollyannic simpleton had appeared in many guises and variations since the 1800s, including in dental advertisements that assured the public of minimal tooth-pulling pain. Permanently named Alfred E. Neuman, the character became Mad magazine's mascot with issue #30. In November 2008, Mingo's original cover featuring the first "official" portrait of Neuman sold at auction for $203,150.
Norman Mingo crafted several Mad covers in 1956-7 before leaving the magazine. He returned to Mad in 1962 and painted most of its front covers until 1976. His last Mad cover appeared on issue #211 (December 1979). Fellow cover artists Jack Rickard and Bob Jones have remarked that Mingo was the only one who could paint the Neuman character perfectly 'on model' every time.
Although Mingo has been named as the artist who created the definitive Neuman face, he created a dramatic variation in 1979—after the nuclear accident at Three Mile Island. With an exaggerated version of the meltdown in the background, on the cooling towers, Alfred abandons his trademark grin and says, "Yes...me worry!"
Semi-retired when he took his first Mad magazine cover assignment, Norman Mingo was the only veteran of the First World War ever to write or draw for Mad.