Mr King co-wrote the group’s best known hit “Sweet Home Alabama”.
A statement posted on the guitarist’s Facebook page said he died at his home in Nashville, Tennessee, on Wednesday. No cause of death was revealed, but he had reportedly been diagnosed with lung cancer.
Gary Rossington, one of the band’s founding members, led the tributes on Thursday and said he was “shocked and saddened” by King’s death.
“Ed was our brother, and a great songwriter and guitar player,” Mr Rossington wrote on the band’s official Twitter account. “I know he will be reunited with the rest of the boys in Rock & Roll Heaven.”
Country music star Charlie Daniels said: “Rest in peace Ed, you left behind some great riffs Buddy.”
Randy Bachman, lead guitarists with Bachman-Turner Overdrive, said King “wrote the anthem of the south with Sweet Home Alabama and was such a talented guitarist.”
King joined Lynyrd Skynyrd in 1972 and worked alongside two other lead guitarists to create the group’s powerful triple-guitar sound on 1970s rock classics like “Free Bird” and “Saturday Night Special”.
He left the group in 1975, two years before a plane crash killed singer Ronnie Van Zant and guitarist Steve Gaines.
King returned to Lynyrd Skynyrd when the band regrouped in 1987, and stayed until 1996, when he retired because of heart problems. He was inducted into the Rock and Roll Hall of Fame as part of the band in 2006.
The California native previously played with the psychedelic rock band Strawberry Alarm Clock.