According to his son-in-law Roy Beagle, Whitman died of heart failure at Orange Park Medical Center in Florida.
Whitman recorded more than 65 albums and sold millions of records. His career spanned six decades, beginning in the late 1940s.
The tenor falsetto and ebony mustache and sideburns became global trademarks - and an inspiration for countless jokes - thanks to the TV commercials 1980s and 1990s that pitched his records.
His 1952 hit "Indian Love Call" was humorously featured in the 1996 movie "Mars Attacks!" It was his high-pitched yodel that caused the Martians' heads to explode. Whitman's other hits included "Have I Told You Lately That I Love You," ''Red River Valley," ''Danny Boy" and "I'll Take You Home Again, Kathleen."
He was a serious musical influence on early rock, and in the British Isles, he was known as a pioneer of country music for popularizing the style there. Whitman also encouraged a teen Elvis Presley when he was the headliner on the bill and the young singer was making his professional debut.
He was born Ottis Dewey Whitman Jr. in Tampa on Jan. 23, 1923, and he worked as a young man in a meatpacking plant, at a shipyard and as a postman.
He was survived by his daughter, Sharon Beagle, and his son, Byron Whitman.
The Associated Press contributed to this report.