Everly died in the Los Angeles suburb of Burbank of complications from lung disease, his wife, Patti, told the Los Angeles Times.
"We are absolutely heartbroken," she said, adding the disease stemmed from a lifetime's smoking.
Phil Everly and brother Don made up the Everly Brothers, one of the biggest pop acts of the 1950s and early 1960s.
They had a string of close-harmony hits including Wake Up Little Suzie, Cathy's Clown, Bye Bye Love, and All I Have To Do Is Dream.
US rock pioneer Duane Eddy, a friend of Everly, said: "It's a terrible, terrible loss - for me, for everybody."