Reynold Ruffins, an illustrator, graphic designer and artist who was an early member of Push Pin Studios, the impish and buzzy design firm founded by his Cooper Union classmates Milton Glaser, Ed Sorel and Seymour Chwast, died on July 11 at his home in Sag Harbor, N.Y. He was 90.

The cause was cardiac arrest, his son Seth said.

Print advertising in the early 1950s was a formal, rather dull affair. Products were mostly hawked using traditional typefaces paired with romantic or idealized photographs and illustrations on the one hand, or a chilly, rational European modernist style — elegant photographs and sans serif type — on the other.

In witty, faux-nostalgic drawings and lettering, Mr. Glaser, Mr. Chwast, Mr. Sorel and Mr. Ruffins, all illustrators, turned the field on its head, and in so doing largely created the postmodern discipline of graphic design, by taking what had been disparate roles — illustration and type design — and putting them together.

“They made entertainment out of design,” said Steven Heller, a former art director at The New York Times Book Review and the editor of “The Push Pin Graphic: A Quarter Century of Innovative Design and Illustration,” a 2004 visual history of the studio’s work. “They did it by using vernacular forms like cartoon, and by going back into styles like Art Nouveau and Art Deco and reinterpreting them. They brought passé back. They brought pastiche into the vocabulary of design and made it cool.”

In his own work, Mr. Ruffins mined late 19th century and early 20th century European imagery like the posters and illustrations of Emil Pretorius or Heinrich Christian Wilhelm Busch, a German cartoonist and illustrator. The kinetic looniness of the German cartoons and the billowing forms of art nouveau taken up by Mr. Ruffins and the other Push Pin illustrators prefigured the trippy, psychedelic imagery that would become the signature look of the late ’60s.

“Reynold played with the forms,” Mr. Heller said. “While they fit into the 20th century continuum, they are definitely his own.”

As Mr. Ruffins recalled later, being Black made him a rarity in the advertising business — an industry that, before the Civil Rights era, was an all-white world of Mad Men. Since his work was his calling card, clients often did not know his race.

“After finishing a job, I’d go meet an art director and there would be some surprises,” Mr. Ruffins told The Sag Harbor Express in 2013. “One-time, I finished a big job — both physically and financially — and had my portfolio under my arm. I was feeling so good. The receptionist looked up and said, ‘The mailroom’s that way.’ The assumption was if you were Black, you were delivering something.”

Reynold Dash Ruffins was born on Aug. 5, 1930, in Queens. His father, John Ruffins, was an appliance salesman for Consolidated Edison, otherwise known as Con Ed, the energy company; his mother, Juanita (Dash) Ruffins, was a homemaker.

Like Mr. Glaser, a high school buddy, he went to the High School of Music & Art, and then Cooper Union, the highly selective and at the time tuition-free arts college in downtown Manhattan. Mr. Ruffins graduated in 1951.

One summer, he and his classmates there, Mr. Glaser and Mr. Chwast, formed a graphics business called Design Plus. They had two clients, Mr. Chwast recalled. One wanted to make a gross of cork place mats (Mr. Ruffins designed the tropical scene they silk-screened onto them) and the other was a monologuist who needed a flier. “Then our vacation was over and we went back to school,” Mr. Chwast said.

Next, Mr. Chwast, Mr. Sorel and Mr. Ruffins had the idea to sell themselves with a digest of type and illustration, a four-page booklet designed as a parody of the Farmer’s Almanac. They called it the Push Pin Almanack and sent it to art directors to drum up work. (Mr. Glaser had gone to Europe on a Fulbright.) It was filled with bits of ephemera — factoids and poems and old-time remedies for toothache, for example — rendered in a neo-nostalgic style all their own. Mr. Ruffins designed the push pin logo. Copies of the Almanack and its successor, the Push Pin Monthly Graphic, are now collectibles for design enthusiasts.

In 1954, Mr. Chwast, Mr. Glaser and Mr. Sorel formed a proper design firm and named it Push Pin Studios, though they had barely any clients, and invited Mr. Ruffins to join.

But Mr. Ruffins had married Joan Young, a classmate at Cooper Union, and they had a baby, so he took a job at a more established firm. In a sign of the times, Joan was asked to leave Cooper Union when she was pregnant. The dean told her she was wasting a spot that could be given to a man. Decades later, the school awarded her a certificate of completion.

When Push Pin Studios established itself, Mr. Ruffins returned, and stayed for about five years, Mr. Chwast said, before going out on his own in 1960. Mr. Sorel, the well-known political cartoonist and New Yorker contributor, left early on, too. Mr. Glaser, of course, would go on to become a co-founder of New York Magazine, create the “I ♥ NY” logo and other iconic designs.

Mr. Ruffins contributed designs for The Urbanite, a short lived culture magazine for “the New Negro,” out in 1961, put together by Byron Lewis, an advertising executive, and others. James Baldwin, Lorraine Hansberry, Langston Hughes and LeRoi Jones also contributed.

“We couldn’t attract any paid advertising,” said Mr. Lewis, who went on to start his own advertising agency, Uniworld, to focus on the Black market. “No mainstream advertiser wanted to advertise in a Negro publication. That’s what we were called then. We were a start-up trying to be different from Ebony and Jet which focused on Black celebrities. Reynold was a pioneer because he was working in the white mainstream advertising world. That was unheard-of for a Black man then. He was a role model.”

Mr. Ruffins later started the design studio Ruffins/Taback, Inc. with his friend Simms Taback. (They had a greeting card company, too, called Cardtricks, featuring the two men’s expressive, arch drawings.)

He collaborated with Jane Sarnoff, a writer, on 14 children’s books, which were offbeat and comedic expositions on whatever topic interested them in any given year, from superstitions to chess to riddles.

His illustrations for “Running the Road to ABC,” by Denize Lauture, a Haitian poet, earned Mr. Ruffins the Coretta Scott King Award for Illustrator-honor in 1997. “Illustrator Reynold Ruffins’ gorgeous single- and double-page gouache pictures capture the cadence of Lauture’s rhythmic text and the vibrant colors of the children’s world,” The Los Angeles Times wrote in 1996.

Joan Ruffins, a painter, died in 2013. In addition to his son Seth, Mr. Ruffins is survived by two other sons, Todd and Ben; a daughter, Lynn Cave, and six grandchildren.

Mr. Ruffins, who taught for just over a decade in the art department at Queens College, began painting full time in the early 2000s, joyous, jazzy and often abstract work he exhibited in Sag Harbor and elsewhere.

“I’ve had the good fortune of almost always enjoying my work, some less of course than others,” he told The Sag Harbor Express. “I probably work harder at easel painting than I did as illustrator because I had the constraints and the need to satisfy the client, although it can be helpful to know what you can’t do.”