Mr. Williams became a major star in 1956, the same year as Elvis Presley, with the Sinatra-like swing number "Canadian Sunset." For a time, he was pushed into Presley imitations such as "Lips of Wine" and the No. 1 "Butterfly."
But he mostly stuck to what he called his "natural style" throughout his career. In 1970, when even Frank Sinatra had temporarily retired, Mr. Williams was in the top 10 with the theme from Love Story. Overall, he had 18 gold records, three platinums, and five Grammy award nominations.
Mr. Williams was also the first host of the live Grammy Awards telecast and hosted the show for seven consecutive years, beginning in 1971.
Movie songs became a specialty, including "Moon River." The Johnny Mercer-Henry Mancini ballad was his most famous song. He never released it as a single because his record company feared lines such as "my huckleberry friend" were too confusing and old-fashioned for teens.
The song was first performed by Audrey Hepburn in the 1961 film Breakfast at Tiffany's, but Mancini thought "Moon River" ideal for Mr. Williams, who recorded it in "pretty much one take" and also sang it at the 1962 Academy Awards. Although "Moon River" was covered by countless artists, Mr. Williams made it his own.
"When I hear anybody else sing it, it's all I can to do stop myself from shouting at the television screen, 'No! That's my song!' " Mr. Williams wrote in his 2009 memoir, titled, fittingly, Moon River and Me.
The Andy Williams Show, which ran in various formats through the 1960s and into 1971, won three Emmys. It featured Mr. Williams performing his stable of hits and bantering with guest stars.
Mr. Williams booked acts ranging from the Osmond Brothers to the Beach Boys, the Temptations, and Smokey Robinson. On one show in 1970, Mr. Williams sang "Heaven Help Us All" with Ray Charles, Mama Cass Elliott, and a then-little-known Elton John, in rhinestone glasses and black cape. Mr. Williams liked him and his breakthrough hit "Your Song" enough to record it himself.
Mr. Williams' act apparently was not entirely an act. The singer's unflappable manner on television and in concert carried through offstage.
"I guess I've never really been aggressive, although almost everybody else in show business fights and gouges and knees to get where they want to be," he once said. "My trouble is, I'm not constructed temperamentally along those lines."
His wholesome image endured one jarring interlude.
In 1976, his ex-wife, former Las Vegas showgirl Claudine Longet, shot and killed her lover, the skiing champion Spider Sabich. The Rolling Stones mocked the tragedy in "Claudine," a song so pitiless it wasn't released until decades later.
Longet, who said the shooting was an accident, spent only a week in jail. Mr. Williams stood by her, escorted her to the courthouse, testified on her behalf, and provided support for her and their children, Noelle, Christian, and Robert.
Also in the 1970s, Mr. Williams was seen frequently in the company of Ethel Kennedy, Robert F. Kennedy's widow. The singer denied any romantic involvement.
Howard Andrew Williams was born in Wall Lake, Iowa, on Dec. 3, 1927. In his memoirs, Mr. Williams remembered himself as a shy boy who concealed his insecurity "behind a veneer of cheek and self-confidence."
Mr. Williams began performing with his older brothers, Dick, Bob, and Don, in the local Presbyterian church choir. Their father, postal worker and insurance man Jay Emerson Williams, was the choirmaster - and the force behind his children's career.
When the young singer was 8, his father arranged for the boys to have an audition on Des Moines radio station WHO's Iowa Barn Dance. They were initially turned down, but father and sons kept returning and were finally accepted.
The brothers joined Bing Crosby in recording "Swinging on a Star" in 1944 for the film Going My Way, and Mr. Williams, barely a teenager, was picked to dub Lauren Bacall's voice on a song for To Have and Have Not. His voice was cut because it didn't sound like hers.
After five years, the three older brothers, who were starting their own families, tired of the constant travel and left to pursue other careers. Mr. Williams initially struggled as a solo act and was so broke at one point he resorted to eating food intended for his two dogs.
A two-year TV stint on Steve Allen's Tonight and a contract with Cadence Records turned things around. Mr. Williams later formed his own label, Barnaby Records, which released music by the Everly Brothers, Ray Stevens, and Jimmy Buffett.
After leaving TV, Mr. Williams headed back to the road, where his many Christmas shows and albums made him a huge draw during the holidays.
He decided to settle in Branson, with its dozens of theaters featuring live music, comedy, and magic acts, and was among the first wave of national entertainers to perform there regularly.
"The fact is, most of my friends in L.A. still think I'm nuts for coming here," he told the Associated Press in 1998.
He and his second wife, the former Debbie Haas, divided their time between homes in Branson and Palm Springs, where Mr. Williams spent his leisure hours on the golf course when Branson's theaters were dark during the period after Christmas.
Retirement was not on his schedule. As he told the AP in 2001: "I'll keep going until I get to the point where I can't get out on stage."
Mr. Williams is survived by his wife and children.