He suffered a cardiac arrest while walking in the Flatiron district, his wife, the former Ethel Leventhal, said. He lived in Pound Ridge, N.Y.

Mr. Renek’s novels, published between the 1960s and ’80s, conveyed social messages in hard-boiled prose. His characters were often motivated by powerful ambition or desperation to escape society’s constraints.

The critic John Leonard, writing in The New York Times, called Mr. Renek’s second novel, “Siam Miami”(1969), “comic, profound and elegantly written.” The book described a beautiful pop singer’s brushes with the sleazy side of show business on the path to stardom.

Mr. Renek’s third novel, “Heck” (1971), was about a nobody who decided to rob a bank in his old Brooklyn neighborhood, Williamsburg, so that he could have a sense of accomplishment.

“His enthusiasm is boundless, his imagination unpredictable and diverting,” the novelist John Deck wrote in The New York Times Book Review. “There is a wealth of talent here that is perhaps spent too lavishly. That it is a real and original talent there can be no doubt.”

Though Mr. Renek’s novels had only limited commercial success, he refused to compromise his writing for more gainful employment; he quit a lucrative job writing for CBS News to devote more time to his novels.

In his book “Namedropping: Mostly Literary Memoirs,” the novelist and critic Richard Elman called Mr. Renek “the single most dedicated novelist I ever encountered.”

“He was respected but not easily published, admired but impoverished,” Mr. Elman wrote. “His works are not sufficiently appreciated; he’s a serious popular novelist who lacks a popular audience.”

Mr. Elman said he had helped Mr. Renek find jobs writing for The New Republic and other publications.

Mr. Renek’s last two published books reached back in time. “Las Vegas Strip” (1975) was a fictionalized account of Bugsy Siegel’s founding of the Flamingo casino in Las Vegas in the 1940s. And “Bread and Circus” (1987) told of Boss Tweed’s corrupt machinations in New York City.

“He wrote of hard-edged lives,” Mr. Elman wrote. “Like Saul Bellow’s people, his characters were great knowers, but they were kept away from intellectual and academic pursuits.”

Morris Renek was born in Manhattan on March 12, 1925, to Jack Renek and the former Dora Flaxer. He grew up poor in Williamsburg, and graduated from Eastern District High School. He served in the Army during World War II, then worked as a copy boy at The New York Herald Tribune.

Mr. Renek studied for a time at the University of Chicago before leaving to write and work as a shrimper in South Carolina. He eventually returned to New York, where he married Ms. Leventhal in 1957. She worked as a social worker to supplement their income.

In addition to his wife, Mr. Renek’s survivors include two daughters, Nava and Naomi, and a grandson.

At his death, Mr. Renek was writing a new novel, “Happy Hour Man,” about a commuter who turns to violence out of boredom. He had also finished one called “The Sea,” about slavery and the Middle Passage. Nava Renek said her family hoped to find a publisher.