Songs like Bye Bye Love and Wake Up Little Susie appealed to the postwar generation of baby boomers, and their deceptively simple harmonies hid greater meaning among the lighter pop fare of the era.
The two broke up amid quarrelling in 1973 after 16 years of hits, then reunited in 1983, "sealing it with a hug", Phil Everly said.
Although their number of hit records declined in the late 1980s, they had successful concert tours in the US and Europe.
They were inducted into the Rock 'n' Roll Hall of Fame in 1986, the same year they had a hit pop-country record, Born Yesterday. Two years earlier, they had success with the up-tempo ballad On the Wings of a Nightingale, written by Paul McCartney.
"As a singer, a songwriter and a guitar innovator, Don Everly was one of the most talented and impactful artists in popular music history," said Kyle Young, CEO of the Country Music Hall of Fame and Museum, in a statement. The brothers were inducted into the Country Music Hall of Fame in 2001.
Don Everly was born in Brownie, Kentucky, to Ike and Margaret Everly, who were folk and country music singers. Phil Everly was born to the couple in Chicago, where the Everlys moved from Brownie when Ike grew tired of working in the coal mines.
The brothers began singing country music in 1945 on their family's radio show in Shenandoah, Iowa.
Their career breakthrough came when they moved to Nashville in the mid-1950s and signed a recording contract with New York-based Cadence Records.
Their breakup came dramatically during a concert at Knott's Berry Farm in California. Phil Everly threw his guitar down and walked off, prompting Don Everly to tell the crowd: "The Everly Brothers died 10 years ago."
The disputes between the brothers even went to court, when Don Everly sued the heirs of Phil Everly in 2017 over the copyright to three of their songs, including Cathy's Clown. The case went all the way to the 6th Circuit Court of Appeals.
But after Phil's death in 2014, Don said that he felt a spiritual message from his brother before he died.
"Our love was and will always be deeper than any Earthly differences we might have had," Don Everly said in a statement in 2014.
While apart, they pursued solo singing careers with little success. Phil also appeared in the 1978 Clint Eastwood movie Every Which Way but Loose. Don made a couple of records with friends in Nashville, performed in local nightclubs and played guitar and sang background vocals on recording sessions.
Don Everly said in a 1986 Associated Press interview that he and his brother were successful because "we never followed trends. We did what we liked and followed our instincts. Rock 'n' roll did survive, and we were right about that. Country did survive, and we were right about that. You can mix the two, but people said we couldn't."
Decades later, their impact on popular music is still evident. In 2013, Green Day's Billie Joe Armstrong and Norah Jones released a loving tribute to the Everlys on their collaborative album Foreverly.