Correction: A photo caption accompanying the print version of the obituary of Mad magazine editor Al Feldstein misidentified two people because of incorrect information provided with the original 1972 photograph from the Associated Press. According the magazine’s editor-in-chief, John Ficarra, the three people pictured were, left to right, associate editor Jerry DeFuccio, Feldstein and associate editor Nick Meglin.

Mad magazine editor Al Feldstein works on page layout in his office at the magazine's New York headquarters in 1972. (Jerry Mosey/AP)

Al Feldstein, who shaped and warped the sensibilities of America’s youth for more than two decades as the editor of Mad magazine and who had a defining influence on modern humor, died April 29 at his ranch near Livingston, Mont. He was 88.

His wife, Michelle Key Feldstein, confirmed his death. She did not cite a specific cause.

Mad was originally a comic book, created by Harvey Kurtzman in 1952. But it was Mr. Feldstein, who became editor in 1956, who transformed Mad into a mass-circulation magazine that exerted a strong, if subversive, influence on generations of young people.

He made the magazine’s gap-toothed mascot, Alfred E. Neuman, a universally recognized image and hired a stable of artists and writers who lampooned politics, religion, Hollywood, advertising and even the magazine itself. The magazine published this disclaimer: “We reject the insinuation that anything we print is moral, theological, nutritious or good for you in any way, shape or form.”

The Mad sensibility of blithe mockery, disengaged disdain and nose-thumbing scorn of pop culture became the model for a new style of humor — and a new way of viewing the world. Mad was perhaps the first publication to build its identity around the mockery of adult hypocrisies. It reached its peak of popularity in the early 1970s, with a circulation of 2.8 million, by reveling in a smart-aleck, adolescent satire and jokes.

Decades later, its mischievous DNA still runs through the skits of “Saturday Night Live,” the spoofs of the Onion, the self-aware political satire of Jon Stewart and Stephen Colbert and the standup routines of countless comedians. In that sense, as Washington Post writer Peter Carlson noted in 1997, it is no exaggeration to call Mad “the most influential American magazine of the postwar era.”

For decades, in order to preserve its sharp satirical edge, the magazine did not accept advertising. It had regular features, including “Snappy Answers to Stupid Questions” and “Spy vs. Spy,” but it built its reputation by puncturing pomposity, often with carefully wrought parodies.

“What we did was to take the absurdities of the adult world that youngsters were facing and show kids that the adult world is not ominpotent,” Mr. Feldstein told the New York Times in 1981. “We told them there’s a lot of garbage out in the world and you’ve got to be aware of it.”

In a Mad sendup, the bland middle-America magazine Better Homes and Gardens became “Bitter Homes and Gardens,” where you could learn how to “convert your spare bedroom into a basement.”

During the Vietnam War, the magazine asked readers to write to FBI Director J. Edgar Hoover to request an “Official Draft Dodger Card.”

In a predictably bizarre encounter, FBI agents paid a visit to Mad’s offices in New York, dropping hints that Hoover didn’t take kindly to such shenanigans.

“Al was a diabolical genius,” Maria Reidelbach, author of “Completely Mad,” a 1991 history of the magazine, wrote in an e-mail to The Post. “He recognized the best of founding editor Harvey Kurtzman’s wildly original comics and then searched out other quirky writers and artists to keep Mad funny, provocative, and fresh for three decades.”

In the second issue that Mr. Feldstein edited, he put the image of the grinning, jug-eared boy, with one eye lower than the other, on the cover, declaring that Neuman was Mad magazine’s candidate for president.

Neuman, a guileless, ubiquitous simpleton, quickly became Mad’s enduring symbol. His all-purpose slogan, “What — me worry?” became familiar well beyond the circle of the magazine’s readers.

Mad fought a prolonged copyright battle in the 1960s with a widow who claimed her husband had created the Neuman character years before. The court ruled in the magazine’s favor, citing advertising and other illustrations using a similar character since the 19th century.

At Mad, Mr. Feldstein hired a staff — always referred to on the masthead as “The Usual Gang of Idiots” — that shared his delight in inspired lunacy. Some of the cartoonists who helped define the magazine’s irreverent tone, including Dave Berg, Mort Drucker, Al Jaffee and Don Martin, stayed on for years. Comedians Sid Caesar, Ernie Kovacs and the team of Bob Elliott and Ray Goulding contributed to the magazine. Other staff writers went on to careers with TV comedies or late-night talk shows.

Mad’s letters to the editor were a special form of comic silliness, with puns, complaints and self-mockery.

“Every time I write you a letter, you never print it,” one reader complained. “So this time, I just won’t write you a letter.”

Albert Bernard Feldstein was born Oct. 24, 1925, in Brooklyn. His father was a dental technician who made false teeth.

In his teens, Mr. Feldstein learned the comic-book business while working in a studio run by cartoonists Will Eisner and Jerry Iger. During World War II, he served in the Army Air Forces, mostly as a sign painter and illustrator.

He began working at EC Comics in 1948 and helped develop such titles as Tales From the Crypt, Weird Fantasy and Weird Science before he was put in charge of Mad. After retiring in 1984, Mr. Feldstein moved to Wyoming and later Montana, where he lived on a 270-acre ranch and became a prolific painter of animals and landscapes. He and his wife, Michelle Key Feldstein, rescued more than 40 dogs and 200 abused or abandoned farm animals, which they kept on their ranch.

Mr. Feldstein’s first marriage, to Clair Szep, ended in divorce; his second wife, Natalie Sigler, died in 1986. In addition to his wife of 25 years, survivors include two daughters from his first marriage; three stepchildren; and five grandchildren.

Mad magazine is still published today, but its circulation has dwindled to about a tenth of what it had been at its height under Mr. Feldstein.

He saw the magazine as a form of civic education and recognized its influence on young people. “It was their pipeline into the truth about what was happening in the country,” Mr. Feldstein said in 2005. “It taught them skepticism.”

But he could never take anything, least of all Mad magazine, too seriously.

“The other day a friend of mine said to me,” a correspondent wrote in a 1956 letter to the editor, “he said, ‘That Mad isn’t fit for idiots.’ I stuck up for your magazine. I said that it was.”