Known for their work with Chic in the late 1970's, Sister Sledge reached the height of their popularity during the disco era but had been recording since the early 1970's. The group was formed in Philadelphia, Pennsylvania in 1971, when the sisters' ages ranged from 12 to 16. They recorded their first single, "Time Will Tell," for the Philly-based Money Back label. For the first few years, the group called itself Sisters Sledge.
In 1972, Sister Sledge signed with ATCO Records and recorded its second single, "Weatherman," which was followed by The Jackson 5-like "Mama Never Told Me" in 1973. It wasn't until 1979, when Chic leaders Nile Rodgers and Bernard Edwards produced "We Are Family", that Sister Sledge really exploded commercially. "He's the Greatest Dancer" and the album's eponymous single both soared to number one on the R&B charts.
In 1989, Kathy left the group to pursue a solo career. Joni passed away on March 10, 2017.