Robert Loomis, a blue-chip editor of old-fashioned sense and persistence who in more than 50 years at Random House encouraged, prodded and befriended William Styron, Maya Angelou, Calvin Trillin and many others, died April 19. He was 93.

His death was announced by Random House, which did not provide additional details.

“I was just one of many who adored and learned from Bob, who inspired several generations of editors and publishers,” Gina Centrello, the company’s president and publisher, said in a statement. “His values and work ethic are permanently embedded in the Random House DNA.”

Mr. Loomis was a final link to the “Golden Age” of publishing after World War II. He joined Random House in 1957, when co-founders Bennett Cerf and Donald Klopfer were running the company. He remained there into his 80s, retiring in 2011 long after most of his peers had died or changed jobs, long after the publisher had been bought by the German media conglomerate Bertelsmann and the industry overall had shed much of its genteel past.

He was dignified, loyal and successful. Among the award winners and bestsellers, fiction and nonfiction, that he helped publish: Styron’s “Sophie’s Choice,” Angelou’s “I Know Why the Caged Bird Sings,” Jonathan Harr’s “A Civil Action” and Neil Sheehan’s “A Bright Shining Lie.”

He spoke softly but acted forcefully, likening a manuscript to a sculpture that required the most precise shaping. “Passages” author Gail Sheehy wrote of his “barely audible critiques emitted from beneath his white pencil mustache.” Angelou would remember his determination to get her to write a memoir, “Caged Bird,” and how he scrutinized every word and punctuation mark. Mr. Loomis spent more than a year working with historian John Toland on revisions for “The Rising Sun,” a Pulitzer Prize winner. Styron, best man at both of Mr. Loomis’s weddings, would speak of his intolerance for bad writing, and his “almost” style of editing that would label a manuscript “almost” ready for publication.

“With Bob,” Styron once said, “you can’t get by with those moments of laziness or failure of clarity or self-flattering turgidity: He pounces like a cobra, shakes the wretched phrase or sentence into good sense or meaning.”

In the 2011 memoir “Reading My Father,” Alexandra Styron described Mr. Loomis and her father as a literary odd couple, the author “all untidy appetite and noisy id,” the editor a “sort of Leslie Howard figure, fair hair always meticulously groomed, his voice as gentle as his demeanor.” Literary agent Sterling Lord remembered a more adventurous side to Mr. Loomis, who for lunch would fly clients in his private plane from Manhattan to Pennsylvania. Seymour M. Hersh, the prizewinning author and journalist, would describe Mr. Loomis as “precise, careful and very direct,” and certain to order a “Jack Daniel’s on the rocks” while only eating “half of his lunch.”

Mr. Loomis was married twice, most recently to Hilary Mills. He had two children, one with each wife.

He was born Robert Duane Loomis in Conneaut, Ohio, on Aug. 24, 1926. Raised in Plain City, Ohio, he attended Duke University, where he would meet such future authors as Styron, Peter Maas and Mac Hyman before graduating in 1949.

After writing at an ad agency, Appleton-Century, and editing at Holt, Rinehart & Winston, he joined Random House, which thought enough of the new hire to pay for a one-bedroom apartment in Greenwich Village that had an asking price of $8,000.

“Donald [Klopfer] said, ‘We hear you want to buy this apartment.’ And I said, ‘Yeah, well, $8,000. I don’t have any money at all,’ ” Mr. Loomis recalled in Al Silverman’s “The Time of Their Lives,” a 2008 publishing history. “Donald pulled out a checkbook and wrote on it ‘eight thousand dollars.’ ”

He would publish literary fiction by Styron and Pete Dexter, history by Sheehan, Shelby Foote and Daniel J. Boorstin, and confessional works by Trillin and Angelou. Along with his many triumphs, Mr. Loomis was also responsible, at least in part, for Edmund Morris’s “Dutch.” It was an authorized biography of Ronald Reagan that came out in 1999 and became a scandal when Morris — winner of the Pulitzer Prize for the Loomis-edited “The Rise of Theodore Roosevelt” — admitted that he didn’t understand his subject and inserted himself as a fictional character.

Critics, historians and Reagan supporters denounced the book and Mr. Loomis, who acknowledged that he was initially horrified by Morris’s experiment, was forced to defend permitting it.

“I really began to believe in it after a while,” Mr. Loomis told the New York Times in 1999. “As the material came in, and we started to talk, this was a book that really went through a metamorphosis. This needed a different creative structure to it and different ways of telling Ronald Reagan’s story using this viewpoint.”

— Associated Press