Sherwood Schwartz, who created and produced two of the most disarmingly silly and enduringly popular series on television, “Gilligan’s Island” and “The Brady Bunch,” died July 12 in Los Angeles. He was 94 and had been hospitalized for an intestinal infection, the Associated Press reported.

“Gilligan’s Island,” a slapstick comedy about seven shipwrecked castaways, was canceled after just three seasons on CBS in the mid-1960s. “The Brady Bunch” — about an idyllic, bell-bottomed family of eight — aired just five seasons, until 1974.

Both were derided by critics as kitschy failures. But fans adored the corny jokes and groan-worthy gags, and the simple-minded shows endeared themselves to a nation beset by civil rights struggles and a war in Vietnam.

Decades after they ended, the series live on in reruns, spinoffs and parodies. Several generations of Americans can hum their plucky theme songs — both of which were co-written by Mr. Schwartz and have become fixtures in the cultural lexicon.

“Masterpiece cheese, I guess that’s what Sherwood Schwartz did better than anybody,” said Robert J. Thompson, a professor of popular culture and television at Syracuse University.

Mr. Schwartz was an Emmy Award-winning veteran writer of “The Red Skelton Show” when he dreamed up “Gilligan’s Island” in the early 1960s. He saw it as something more than comedy.

“I knew that by assembling seven different people and forcing them to live together, the show would have great philosophical implications,” he told Time magazine in 1995. “On a much larger scale this happens all the time. Eventually, the Israelis are going to have to learn to live with the Arabs. We have one world, and ‘Gilligan’s Island’ was my way of saying that.”

“A social microcosm,” he called it when he pitched the idea to CBS founder William Paley, who shuddered at the description, according to Mr. Schwartz’s 1994 memoir, “Inside Gilligan’s Island.”

“It’s a funny microcosm!” Mr. Schwartz reassured him.

The show was brutally panned upon its debut in the fall of 1964. “ ‘Gilligan’s Island’ is a television series that never should have reached the air this season, or any other season,” wrote Hal Humphrey of the Los Angeles Times.

“A more inept, moronic or humorless show has never appeared on the home tube,” wrote Rick DuBrow of United Press International.

Nevertheless, viewers flocked to watch the antics of the seven characters who found themselves stuck in one another’s company after setting sail for what they expected to be a “three-hour tour.”

Bob Denver played the bumbling title character, an assistant to the Skipper (Alan Hale Jr.). Ginger was the sexpot movie star played by Tina Louise, and her virginal counterpart was Mary Ann, played by Dawn Wells. The cast was rounded out by a pair of snobby millionaires (Jim Backus and Natalie Schafer) and the Professor (Russell Johnson), whose technical skills were never enough to save the marooned tourists from their fate.

Despite its impressive ratings, “Gilligan’s Island” had few fans among CBS executives and was canceled abruptly in 1967.

Mr. Schwartz said he interviewed 464 young people to find the stars of his next big hit, “The Brady Bunch,” which premiered in 1969. It starred Florence Henderson and Robert Reed as Carol and Mike Brady — the previously married mother and widowed father who create a suburban family of six wide-eyed, deeply sincere children.

Like “Gilligan’s Island,” “The Brady Bunch” was a critical failure and commercial success that elicits tender mocking from fans and has achieved a sort of cultural immortality in syndication, offshoot films and stage productions.

“A Sherwood Schwartz production tended to be without guile, without subtext, without pretension,” Thompson said in an interview Tuesday. “It doesn’t have to be a complex, dense, literary kind of thing to be beloved, and sometimes ‘The Brady Bunch’ was just what the doctor ordered.”

Sherwood Charles Schwartz was born Nov. 4, 1916, in Passaic, N.J., and grew up planning to become a doctor. After finishing pre-med studies at New York University, he went west in 1938 to earn a master’s degree in biology at the University of Southern California.

He entered the entertainment business on a lark — his brother was working on Bob Hope’s radio program, and Mr. Schwartz started writing jokes to earn extra money. Hope liked his work and offered to hire him.

“It was the Depression, so I said, ‘I’ll take the job,’ and I’ve been in show business ever since,” he said in 2008.

During World War II, Mr. Schwartz wrote for the Armed Forces Radio Service. After the war, he shifted to television and wrote for 1950s and ’60s shows including “I Married Joan” and “My Favorite Martian.” He shared an Emmy for his work as head writer on “The Red Skelton Show” in 1961.

Survivors include his wife, Mildred; four children; and several grandchildren and great-grandchildren.

Mr. Schwartz created several other series, including “Dusty’s Trail,” featuring Bob Denver as a 19th-century migrant lost in the desert of the American West. But he built the bulk of his later career on the foundations of “Gilligan’s Island” and “The Brady Bunch.”

He said he was not bothered by critical reception of those sitcom hits. “I honestly think I could sit down and write a show tonight that the critics would love, and I know it would be canceled within four weeks,” he told the Los Angeles Times in 1990. “We write and produce for people, not for critics.”