Tom Wilson Sr., 80, who displayed an uncanny knack for turning lovably sweet and round cartoon characters — foremost “Ziggy” — into embraceable commercial juggernauts, died Sept. 16 at a hospital in Cincinnati. He had pneumonia.

The death was confirmed by Universal Uclick, which continues to syndicate “Ziggy.” The cartoonist’s son, Tom Wilson Jr., inherited day-to-day operations of the comic strip in 1987.

Centered on a hapless everyman, “Ziggy” used graphic simplicity and pithy, empathetic wit to achieve uncommon pop-cultural omnipresence.

Forty years after its launch by the fledging Universal Press Syndicate (now Universal Uclick), “Ziggy” is syndicated to more than 500 newspapers and continues to sell millions of dollars worth of T-shirts, coffee mugs and desk calendars, according to parent company Andrews McMeel Universal.

“Ziggy’s” bald, big-nosed and barefooted protagonist intentionally exists in a world devoid of specific time or trend, place or profession, age or marital status.

“I get a lot of letters — especially from teenage girls,” the elder Mr. Wilson told the Indianapolis Star in 2000. “They say, ‘Ziggy ought to have a girlfriend. He ought to have a family.’ I write back and tell them, ‘He does have a girlfriend. His girlfriend is you!’ ”

As the abstracted everyman, Ziggy is all about the universality of the beleaguered moment, whether the comic obstacle on that day is an appliance or a pet or another person or even just one’s own admitted ineptitude.

The cartoonist chose the name “Ziggy” because a “Z” surname represented the student who would always be last in any class’s alphabetical roll call.

Among Mr. Wilson’s earliest influences were the “Laurel and Hardy” movies he watched as a youngster.

“Before berating Laurel, Hardy would always turn to the camera and make eye contact with the audience, establishing an emotional rapport and kind of comic empathy,” he told the Cleveland Plain Dealer in 1993. “That’s why so often you see Ziggy looking out at you from the panel. Sometimes Ziggy speaks to us and sometimes for us.”

Thomas Albert Wilson was born Aug. 1, 1931, in Grant Town, W.Va. His father was a stonemason who later moved the family to Pennsylvania for work as a coal miner.

“I grew up around people who labored for a living,” Mr. Wilson told the Indianapolis Star. “So drawing funny pictures didn’t seem like it was really work.”

After Army service, Mr. Wilson graduated from the Art Institute of Pittsburgh in the mid-1950s before starting a decades-long career with American Greetings in Cleveland. He became a top executive in the creative development division and headed teams that developed such warm and fuzzy characters as the Care Bears and Strawberry Shortcake and helped popularize those creations through savvy licensing

While at American Greetings, Mr. Wilson developed a comic strip featuring a small elevator operator who offered political and topical commentary; the strip didn’t sell, but the character was the direct precursor to Ziggy.

In the late 1960s, Mr. Wilson resuscitated his little character for American Greetings’ new Sunbeam Library line of humorous music books. “When You’re Not Around” — made to send to somebody you missed — sold a half-million copies, Mr. Wilson’s son told The Washington Post.

The wife of a Universal Press Syndicate founder sent her husband one of the books, and it wasn’t long before he decided to sign Mr. Wilson.

Launched in 1971, “Ziggy” made its way into pop culture, from best-selling books to references on popular TV sitcoms. In 1983, “Ziggy’s Gift” — co-written by Mr. Wilson — won an Emmy Award for best animated program.

Mr. Wilson, who moved into a nursing home nearly a decade ago after suffering strokes and lung cancer, was also a painter. His work has been exhibited at the Cleveland Museum of Art and the Society of Illustrators show in New York.

In addition to his son, survivors include his wife, the former Carol Sobble; two daughters; and five grandchildren.

When Tom Wilson Jr., 53, was a teenager, his father began sharing with him the secrets of what made “Ziggy” such a success.

“When I was young, we would go to Bob’s Big Boy restaurants on Saturdays for breakfast,” the younger Wilson told The Post. “He would turn over their place mats and draw Ziggy about ready to fall in a manhole, a safe would be falling toward him, and then Dad would say: ‘I want you to save Ziggy’ — I would have to draw a contraption so Ziggy would avoid this horrible thing.

“Then Dad would say that there’s just one rule: ‘You have to throw out the first idea.’ You couldn’t use your first solution.”