While still in high school, he was an apprentice in the studio of Lucian Bernhard, the great German graphic designer.
After early success as an art director at Young & Rubicam and Carl Ally, winning the Gold Medal of the Art Directors Club of New York, he left advertising to become an illustrator, author and puzzle maker.
He wrote The Nutty News and has illustrated many books, such as a series of children's books with Judi Barrett, including Cloudy with a Chance of Meatballs and Animals Should Definitely Not Wear Clothing.
During the 1970s, Barrett had many comic strips in the National Lampoon "Funny Pages", of which the best remembered is perhaps "Politenessman".
He became the magazine's art director, giving it a style described as "crisp" and "smart".