Andy Williams, the affable, boyishly handsome crooner who defined both easy listening and wholesome, easygoing charm for many American pop music fans in the 1960s, most notably with his signature song, “Moon River,” died on Tuesday night at his home in Branson, Mo. He was 84 and also had a home in ** ******, Calif.

The cause was complications from cancer, his publicist, Paul Shefrin, said. Mr. Williams, who had continued to perform until last year, announced in November that he had bladder cancer.