Bob Edwards, the host of NPR’s “Morning Edition” for nearly a quarter-century, whose rich baritone and cool demeanor imbued his radio broadcasts with authority in reaching millions of listeners, died on Saturday in Arlington, Va. He was 76.

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

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 a co-host of “All Things Considered,’’ the public broadcaster’s signature evening newsmagazine of interviews, analysis and features. Its success led to the spinoff “Morning Edition” in 1979.

Mr. Edwards began as a 30-day temporary host of that program before going on to serve as its anchor for 24 and a half years.

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

Susan Stamberg, his co-host on “All Things Considered,” in an interview with NPR for its obituary about Mr. Edwards, described their oil-and-vinegar chemistry.

“We had five good — if rocky — years together, until we sort of got one another’s rhythm, because he was Mr. Cool, he was Mr. Authoritative and straight ahead,” she said. “I was the New Yorker with a million ideas and a big laugh. But we really adjusted rather well.”

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

On “Morning Edition,” Mr. Edwards interviewed thousands of prominent figures in the news, but also included features on the singer Dolly Parton and the renowned baseball announcer Red Barber, with whom he conducted a popular weekly segment of commentary.

Mr. Edwards was ousted from “Morning Edition” in 2004, a move that led to protests from listeners and reached the reached the halls of Congress, where Senator Dick Durbin, Democrat of Illinois, 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’s departure from the program, many disheartened and some suggesting ageism. Mr. Edwards was about to turn 57.

He discussed his departure on the air with his NPR colleague Scott Simon, saying “tastes change, and they have different ideas about the program and who should be doing it.” He was replaced by Steve Inskeep and Renee Montagne. (The program today is hosted by Mr. Inskeep, Leila Fadel, Michel Martin and A. Martínez.)

Robert Alan Edwards was born in Louisville on May 16, 1947, to Joseph and Loretta (Fuchs) Edwards. His father worked for the city’s 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 he 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 the Armed Forces Radio and Television. He went on to earn a master’s degree in journalism at American University in Washington. He shed his Kentucky accent and worked briefly at WTOP in Washington before joining NPR.

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

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

Mr. Edwards married Ms. 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 phone interview, Ms. Johnston said that Mr. Edwards was long upset that NPR had pushed him from the host’s chair of “Morning Edition” several months short of a full 25 years. “He never got over that,’’ she said.

After his final “Morning Edition” broadcast, on April 30, 2004, he was assigned to be an NPR correspondent, but he left soon after when he was approached to host a program on SiriusXM Radio; “The Bob Edwards Show,” as it was called, ran through 2014. He also appeared on “Bob Edwards Weekend” on public radio stations.

“He was a stickler for even the tiniest of 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.”