Close friend and WVON radio host Pam Morris says Walker died Friday morning of respiratory failure in at RML Specialty Hospital in Chicago.
Morris says Walker was "a living legend" who was responsible for launching more than a dozen careers of gospel artists.
Walker formed her own gospel group, the Caravans, as a young woman and was a protege of gospel star Mahalia Jackson.
U.S. Congressman Bobby Rush called Walker a voice for the civil rights movement. He says her music was "a healing balm to those who struggled for justice."
Walker was lifelong Chicago resident and member of the West Point Baptist Church. Funeral arrangements are pending.