A publicist for the entertainer's family said he died Tuesday night at his home in Branson.Williams had said in November 2011 that he was diagnosed with bladder cancer but planned to continue performing at the namesake theater he built in Branson in 1992.
The clean-cut Iowa native began singing with his brothers as a child, and his easy style and mellow voice led President Ronald Reagan to call Williams "a national treasure."
Though his version of "Moon River" made him world famous, it was among his many hits, including "Butterfly" and "Can't Get Used to Losing You."
The Taney County Coroner's Office confirmed Wednesday afternoon that Williams died at his home at 10:45 Tuesday evening.
He is survived by his wife Debbie and his three children, Robert, Noelle and Christian.