Publicist Don Murry Grubbs said Monday night that the guitarist died in his sleep of natural causes Saturday at his Chicago home.
Swanland joined the band in 1985 after it had split up and regrouped. He was the longest running member of the group except for founding member Doug Gray.
The group is best known for its 1977 Top 40 hit “Heard It In a Love Song.” Their sound is a blend of rock, country and gospel.
Swanlund’s funeral will take place Saturday at the Good Shepherd Memorial Park in Boiling Springs, S.C.
He’s survived by his sister, three grandchildren, a son, William “Billy” Swanlund, and his lifelong partner, Stacey Schmaren.