Jackson, known as the Queen of Gospel, was a musical legend who helped bring gospel from church to mass audiences. She mentored Aretha Franklin and Della Reese, and in 1961 was the first gospel singer to win a Grammy. She was also instrumental to the civil rights movement, especially as a good friend of King's.

Shortly after meeting King at the National Baptist Convention in 1956, Jackson agreed to sing at a fundraising rally for the Montgomery bus boycott. After that, she frequently accompanied King to perform at rallies and events. Her voice became the soundtrack of the civil rights movement,