Bob Barker, the consistently good-natured host of “The Price Is Right,” the longest-running game show in American television history, and one of the country’s best-known advocates for animal rights, died on Saturday at his home in the Hollywood Hills section of Los Angeles. He was 99.

His death was announced by a spokesman, Roger Neal.

Mr. Barker was a fixture of daytime television for half a century — first as the host of “Truth or Consequences,” from 1956 to 1974, and, most famously, starting in 1972, on “The Price Is Right.”

He began his 35-year stint as host of “The New Price Is Right,” as it was then known, when it made its debut on CBS as a revised and jazzed-up version of the original “The Price Is Right,” which had been on the air from 1956 to 1965. (The “New” was soon dropped from the name.) He was also host of a weekly syndicated nighttime version from 1977 until it was canceled in 1980.

Almost a decade before he retired in 2007, Mr. Barker estimated that during his tenure more than 40,000 contestants had heeded the announcer’s familiar call to “come on down!” and collected some $200 million in small and large prizes, from beach blankets to Buicks, by guessing the prices of various objects.

Mr. Barker won 14 Daytime Emmy Awards as host of “The Price Is Right” and four more as executive producer (as well as a lifetime achievement Emmy in 1999). He once said that the show had lasted as long as it did because “all our games are based on prices, and everyone can identify with that.” He added, however, that he personally never knew the price of anything, and that if he were ever a contestant on such a show he would be “a total failure.”

Mr. Barker was widely known for his longstanding dedication to the cause of animal rights. He quit as master of ceremonies for both the Miss USA and Miss Universe pageants in 1988 because they gave fur coats as prizes. He also protested the mistreatment of animals by their trainers on the sets of various movies and television shows. He ended every installment of “The Price Is Right” by saying: “Help control the pet population. Have your pet spayed or neutered.”

Robert William Barker was born on Dec. 12, 1923, in Darrington, Wash. His father, Byron, was a power line foreman who in 1929 died from complications of injuries he had received in a fall from a pole several years earlier. Shortly thereafter, his mother, Matilda (Tarleton) Barker, took a job teaching in Mission, S.D, on the Rosebud Indian Reservation.

“Cowboys tied up their horses at hitching rails,” Mr. Barker recalled of those years. “It was like I was growing up in the Old West.”

When Mr. Barker was 13, his mother married Louis Valandra, a tire salesman, and they moved to Springfield, Mo. He received a basketball scholarship to Drury College in Springfield but dropped out to enlist as a Naval Aviation cadet when World War II broke out.

He was waiting for a combat assignment when the war ended, and he was discharged as a lieutenant junior grade. He returned to Drury, majored in economics and graduated summa cum laude in 1947.

Even before he earned his degree, Mr. Barker had begun his first radio job, at KTTS in Springfield, where he was a disc jockey, a news writer, a sportscaster and a producer. After college he worked at WWPG in Palm Beach, Fla., and KWIK in Burbank, Calif.

In 1945, he married Dorothy Jo Gideon, his high school sweetheart, who once explained the secret of their marriage this way: “I love Bob Barker. And Bob Barker loves Bob Barker.” She died in 1981, and Mr. Barker never remarried.

Mr. Barker is survived by his half brother, Kent Valandra. Mr. Barker’s longtime friend Nancy Burnet, a fellow animal rights activist who had been overseeing his care — and about whom he wrote in his autobiography, “Our relationship has gone on for 25 years, off and on. Mostly on.” — is an executor of his estate.

Mr. Barker’s big break came in 1956 when the producer Ralph Edwards heard him on KNX, a Los Angeles radio station, and asked him to audition for “Truth or Consequences,” a long-running game show (it had begun on radio in 1940) on which contestants were required to perform wild stunts. He got the job, and he and Mr. Edwards became lifelong friends.

Mr. Barker was still the host of “Truth or Consequences” when he was offered “The Price Is Right” in 1972, and for two years those jobs overlapped. For a long time after that he was among the busiest people on television, with duties that also included hosting the Rose Bowl parade and the Pillsbury Bake-Off for most of the 1970s and ’80s.

He occasionally showed up in movies as well, almost always as a comically exaggerated version of himself. His most memorable appearance was in the 1996 comedy “Happy Gilmore,” in which he gleefully engaged in a brawl with the title character, a boorish hockey player turned golfer played by Adam Sandler.

To many viewers “The Price Is Right” was, as one critic put it, among television’s last “islands of wholesomeness.” That image was challenged in 1994 when Dian Parkinson, who for almost 20 years had been a model on the show — one of the so-called Barker’s Beauties, whose main function was to display the prizes — sued Mr. Barker for sexual harassment.

Ms. Parkinson, who had left the show the year before, said she had sex with Mr. Barker because she thought she would lose her job if she didn’t. In response, Mr. Barker acknowledged that he and Ms. Parkinson had had a relationship for a number of years, beginning in 1989, but insisted that it had been consensual.

“She told me I had always been so strait-laced that it was time I had some hanky-panky in my life,” he said, “and she volunteered the hanky-panky.” Ms. Parkinson withdrew the suit in 1995 because, she said, she lacked both the emotional endurance and the money to pursue it.

Mr. Barker announced his retirement in October 2006. “I will be 83 years old on Dec. 12,” he said at the time, “and I’ve decided to retire while I’m still young.”

His final episode as host of “The Price Is Right” was taped on June 6, 2007, and shortly shown twice on June 15: first in its regular daytime slot and again in prime time.

After an extensive search, the comedian Drew Carey was chosen as Mr. Barker’s successor in July 2007. In an interview with The Times, Mr. Carey called Mr. Barker a “legend” and praised him for the “empathy” he showed contestants.

“He wants them to win. You can hug him,” Mr. Carey said. “He went from being your dad and your uncle to your grandfather.”

Mr. Barker returned to the show as a guest in 2009 to promote his autobiography, “Priceless Memories,” and again in 2013, to celebrate his 90th birthday, and 2015, as the unannounced guest host, an April Fool’s Day gag. He promised to come back when he turned 100.

“People ask me, ‘What do you miss most about “Price is Right?”’ And I say, ‘The money,’” Mr. Barker said in a 2013 interview with Parade magazine. “But that is not altogether true. I miss the people, too.”

Richard Severo, a Times reporter from 1968 to 2006, died in June. Peter Keepnews and Chris Cameron contributed reporting.