Few people old enough to be awake during prime-time hours in the 1980s emerged from the era without encountering the work of Mr. Jacobs, a onetime nonfiction writer who brought to television a literary sensibility that helped broaden prevailing notions of what the medium could do.

TV writers at the time generally went unheralded, with celebrity reserved for the on-screen talent and the characters they brought to life. So while Mr. Jacobs was not a household name, his creations were — as evidenced by the ubiquity of the catchphrase “Who shot J.R.?,” a reference to a plot point in the most famous episode of “Dallas.”

J.R. Ewing, memorably portrayed by actor Larry Hagman, was the dastardly oil baron at the center of “Dallas,” which premiered on CBS in 1978 and aired for more than 350 episodes before its original run ended in 1991.

A saga about the intrigue and affairs, lust and revenge of an affluent Texas oil and ranching family, the show attracted tens of millions of viewers, becoming one of the most watched programs on television.

Robert Thompson, a professor of television and popular culture at Syracuse University in New York, ranks “Dallas” among the most influential entertainment programs in the history of TV.

When “Dallas” premiered, serialized soap operas aired in the afternoon, but most prime-time evening programming was episodic, allowing viewers to tune in and follow any installment without having seen the previous ones.

“Dallas,” by contrast, followed in the tradition of the 1960s prime-time soap “Peyton Place,” with a narrative that developed over the course of the season and the show.

“One of the things that make television an art form like no other is the idea that it can tell stories that keep on going and going and going,” Thompson said in an interview.

By demonstrating to TV executives that serialization could be successful not only in the afternoon but also during prime time, he added, “Dallas” helped pave the way for acclaimed programs of more recent years including “The Sopranos,” “The Wire,” “Mad Men” and “Breaking Bad.”

“All the things that we now value [in television] are based on the ability to develop stories over time, to develop characters over time,” Thompson said. “What would ‘The Wire’ have been if every single episode solved a new crime?”

“Dallas” was also notable, according to Thompson, for placing an ignoble character in the leading role, as opposed to the more heroic figures generally featured in dramatic television up to that point. As a “manipulative, Machiavellian, evil character,” Thompson said of J.R., he “opened up much more sophisticated territory” for television.

Mr. Jacobs had resisted pressure on the set to soften the character of J.R. “If the show was to be a hit, we’d need the evilest, baddest type of guy for the central character,” he told The Washington Post in 1979. “Bigger and badder than life.”

Mr. Jacobs shifted his focus early in the run of “Dallas” — before the tour de force “Who shot J.R.?” episode — to work on “Knots Landing,” another soapy hit that aired on CBS from 1979 to 1993. Set in a Southern California cul-de-sac, the show followed the decidedly less sordid lives of several middle-class couples, including one drawn from “Dallas.”

Although not as influential as its predecessor, “Knots Landing” was also wildly popular and in some ways represented what Thompson described as Mr. Jacobs’s greater “artistic achievement.”

“There was never anything bigger-than-life about ‘Knots,’” Mr. Jacobs told the Wall Street Journal in 1989. “When you watch ‘Dallas,’ you’re watching them. When you watch ‘Knots,’ you’re watching us.”

David Arnold Jacobs was born in Baltimore on Aug. 12, 1939. His father, he told the Television Academy Foundation in an oral history, was a bookie, a billiards champion, a crooner and a songwriter before his mother, a homemaker, “took him away from all that.”

Mr. Jacobs remembered his father with immense affection and reflected sadly on how much he despised the jobs — driving a cab, selling insurance, laboring in a lamp factory — that he held down to support the family. Growing up, Mr. Jacobs recalled, he watched his father and told himself, “I’m never going to do that. I’m never going to go to work hating what I do.”

Mr. Jacobs was enchanted by movies as a boy and said he went 19 times to see “The Treasure of the Sierra Madre” starring Humphrey Bogart.

He was, by his own account, a poor student but a precocious artist and enrolled at the Maryland Institute College of Art to study painting, receiving a Bachelor of Fine Arts degree in 1961. He moved immediately to New York, where he did graduate work in art history at Hunter College, and where he became a writer for Grolier encyclopedias.

In the early years of his career, Mr. Jacobs wrote nonfiction books, some for young adults and some for general readers, on topics including Renaissance painting, the Byzantine Empire, a New York police precinct, and the lives of composer Ludwig van Beethoven, President Woodrow Wilson and silent-movie star Charlie Chaplin.

Mr. Jacobs also wrote short stories and magazine articles, many of them about architecture, and later reflected that the work prepared him well for a career in TV writing.

“I had never planned it that way, but writing for magazines is the perfect apprenticeship for television,” the Hollywood Reporter quoted him as saying. “You have to build the character fast, and you have to write dramatically. The nonfiction helped with the size and the technical restrictions, and the fiction got me into the kind of storytelling that you need in television.”

Mr. Jacobs’s first marriage was to Lynn Oliansky. When they divorced and she moved with their daughter to Los Angeles, Mr. Jacobs followed in 1976. His former wife became his agent, and her husband, John Pleshette, acted in “Knots Landing.”

Mr. Jacobs was a story editor and writer for shows including the crime series “Kingston: Confidential” and “Family,” a drama with executive producers including Aaron Spelling, before “Dallas” premiered.

Although “Dallas” preceded “Knots Landing” on the air, Mr. Jacobs pitched “Knots Landing” first to TV executives. He based his concept on director Ingmar Bergman’s “Scenes From a Marriage,” a 1970s TV miniseries that was adapted for film.

When Mr. Jacobs and his creative partner, Michael Filerman, presented the idea to a production company, executives replied that they wanted “something glitzier. More of a saga.”

“As soon as we left, as we’re driving back,” Mr. Jacobs told Texas Monthly in 2018, “I said, ‘Well, a saga. That means Texas ranches.’” He had visited Texas only once and had never been to Dallas.

After “Dallas” and “Knots Landing,” Mr. Jacobs co-created “Paradise,” a western that aired on CBS from 1988 to 1991, and “Bodies of Evidence,” which aired from 1992 to 1993, about a team of homicide detectives including one played by George Clooney.

More than three decades after its premiere, “Dallas” was given a short-lived reboot on TNT, with Hagman reprising his role as J.R. before his death in 2012.

Mr. Jacobs’s survivors include his wife of 44 years, the former Diana Pietrocarli of Los Angeles; a daughter from his first marriage, Albyn Hall of London; two children from his second marriage, Aaron Jacobs of Fairfax, Calif., and Molly Jacobs of Los Angeles; and two granddaughters.

Reflecting on the popularity of “Dallas,” with its depiction of decadent extravagance, Mr. Jacobs told an interviewer that the show “represents the beginning of an era” that ended with the financial collapse of 2008 — a time “in which all of our values as a people have been terribly screwed up.”

“I think ‘Dallas’ was trying — at least in my head and heart — to show that,” he said, according to the Hollywood Reporter. “It was never trying to glorify that world.”