Bob Edwards, host of NPR’s “Morning Edition” for nearly a quarter-century, whose rich baritone and calm demeanor imbued his radio broadcasts with authority to reach millions of listeners, died Saturday in Arlington, Virginia. He was 76 years old.

His death, at a rehabilitation center, was due to heart failure and complications from bladder cancer, said his wife, Windsor Johnston.

Mr. Edwards, a Kentucky native who knew from an early age that he wanted to be in radio, joined NPR in 1974, during the Watergate hearings. That year, he became co-host of “All Things Considered,” the public broadcaster’s exclusive late-night magazine of interviews, analysis and features. Its success led to the spin-off “Morning Edition” in 1979.

Mr. Edwards began as a temporary host of that show for 30 days before serving as host for 24 and a half years.

“Bob Edwards understood the intimate and clearly personal connection with audiences that distinguishes audio journalism from other media,” said NPR CEO John Lansing. said in a statement“and for decades was a trusted voice in the daily lives of millions of NPR listeners.”

Susan Stamberg, his “All Things Considered” co-host, in an interview with NPR for her obituary on Edwards, described the chemistry of oil and vinegar.

“We had five good, although difficult, years together, until we got into each other’s rhythm, because he was Mr. Cool, he was Mr. Authoritative and direct,” he said. “I was the New Yorker with a million ideas and a big laugh. But we really adapted pretty well.”

She called him “the voice we wake up to” for a quarter of a century.

In “Morning Edition,” Mr. Edwards interviewed thousands of prominent news figures, but also included articles about singer Dolly Parton and renowned baseball announcer Red Barber, with whom he directed a popular weekly segment of comment.

Mr. Edwards was booted from “Morning Edition” in 2004, a move that sparked protests from listeners and reached the halls of Congress, where Sen. Dick Durbin, D-Ill., rose on the Senate floor to object, calling Mr. Edwards “the most successful morning voice in America.”

An NPR Ombudsman, Jeffrey A. Dvorkin, wrote at the time that 35,000 listeners had commented on Mr. Edwards’ departure from the show, many of them disheartened and some suggesting age discrimination. Mr. Edwards was about to turn 57 years old.

He discussed its airing with NPR colleague Scott Simon, saying that “tastes change and they have different ideas about the show and who should do it.” He was replaced by Steve Inskeep and Renee Montagne. (Today’s program is presented by Mr. Inskeep, Leila Fadel, Michel Martin and A. Martínez.)

Robert Alan Edwards was born in Louisville on May 16, 1947, the son of Joseph and Loretta (Fuchs) Edwards. His father worked for the city government. Bob Edwards knew he had a voice for radio when, as a child, he would answer the phone and callers would say, “Hello, Mr. Edwards,” assuming it was his father, he told Mr. Simon.

After graduating from the University of Louisville in 1969, he was drafted and sent to South Korea, where he worked for Armed Forces Radio and Television. He later earned a master’s degree in journalism from American University in Washington. He ditched his Kentucky accent and worked briefly at WTOP in Washington before joining NPR.

In 2000, Edwards won a Peabody Award for “Morning Edition,” which the awards committee described as “two hours a day of in-depth news and entertainment expertly directed by a man who embodies the essence of excellence in radio.”

In addition to his wife, Ms. Johnston, an NPR news anchor and reporter, he is survived by two daughters from a previous marriage, Susannah and Eleanor Edwards, and a brother, Joe. His marriages to Joan Murphy and Sharon Kelly ended in divorce.

Edwards married Johnston in 2011. They had met several years earlier, when she interviewed him for WHYY in Philadelphia about a book he wrote, “Edward R. Murrow and the Birth of Broadcast Journalism.” He wrote two other books, “A Voice in the Box: My Life in Radio” and “Fridays with Red: A Radio Friendship.”

In a telephone interview, Ms. Johnston said that Mr. Edwards had long been upset that NPR had ousted him from the “Morning Edition” anchor chair several months before his full 25th birthday. “He never got over that,” he said.

After his last broadcast of “Morning Edition,” on April 30, 2004, he was assigned as an NPR correspondent, but left shortly after when he was approached to host a show on SiriusXM Radio; “The Bob Edwards Show” as it was called, ran until 2014. It also appeared in “Bob Edwards Weekend” on public radio stations.

“He was very strict about even the smallest details and lived by the philosophy that ‘less is more,’” Ms. Johnston wrote on Facebook. “He helped pave the way for the younger generation of journalists who continue to make NPR what it is today.”