His sister, Catherine Thomas, told The Associated Press that Harris passed away Friday morning from congestive heart and lung failure after being rushed to a hospital.
The Richmond native was born Feb. 9, 1947, and grew up in a musical family. His father was a guitarist and his mother led the church choir, Thomas said.
In his teens, Harris was tall for his age and was able to get into clubs to watch musicians perform, she said.
"He always appeared to be older, which gave him a lot of ins to a lot of older places," Thomas joked.
She said he didn't drink in the clubs back then, but he was pursuing his career. Music, she said, "was his life."
Harris made the rounds with several music groups in the 1960s, including the Charmers, Frankie Lymon's Teenagers and Nat Turner's Rebellion.
He then joined the Delfonics in the early 1970s, replacing Randy Cain in the group known for their hits "La-La (Means I Love You)" and "Didn't I (Blow Your Mind This Time)."
Harris left the group in 1974 to pursue a solo career. He recorded a string of R&B singles, including "Love Won't Let Me Wait," which peaked at No. 5 in the U.S. Billboard Hot 100 chart and was certified as a gold record by the Recording Industry Association of America. The song was covered by Johnny Mathis and Deniece Williams in 1994 and again by Luther Vandross on his 1988 album "Any Love."
Harris last performed in 2011 at a reunion show with some of the members of the Delfonics, Thomas said.