Staples had suffered a concussion recently in a fall near his home in suburban Dolton.
He and his group gained fame in the 1960s by singing music that urged social and religious change. He was known for both his songwriting and his guitar playing, in which he fused gospel with the blues.
Born to a poor Winona, Miss., family on Dec. 28, 1915, Staples dropped out of school after the eighth grade to pick cotton.
Staples sang with a gospel group, the Golden Trumpets, before moving with his wife, Oceola, to Chicago in 1936, where he performed with the Trumpet Jubilees.
Staples said his earliest exposure to music came in the church. It wasn't until he was in his teens that he heard the blues. He listed Bessie Smith, Ma Rainey and Blind Lemon Jefferson among his favorites.
Staples formed the group bearing his name in 1948. Originally composed of son Pervis and daughters Mavis and Cleotha, the Staple Singers began as a gospel group that performed in Chicago churches, backed by his minimalist playing. Mavis, then 7 years old, sang bass in the group.
Their first recordings came in the 1950s.
It was during the 1960s that the Staple Singers switched to protest, inspirational and contemporary music, reflecting the civil rights and anti-war protests of the time.
"But we just kept on singing and praying, and we let our music carry the message," Staples said afterward. "When people realized that our music still had the message of love, our audience grew -- old people came back, and new people kept coming."
The Staple Singers gained a huge audience with their first No. 1 hit "I'll Take You There" in 1972 and followed with Top 40 hits "Respect Yourself," "Heavy Makes You Happy," and "If You're Ready (Come Go With Me)."
In 1975 on Curtis Mayfield's Custom label, the Staple Singers released "Let's Do It Again," the title track of the film starring Bill Cosby and Sidney Poitier.
While the Staple Singers enjoyed success in the 1980s, "Pops" Staples began a solo career and tried his hand at acting.
His 1992 "Peace to the Neighborhood" garnered a Grammy nomination, and in 1994 he released "Father, Father," winning a Grammy.
Staples is survived by his children, Cleotha, Pervis, Yvonne -- who replaced Pervis in the group -- and Mavis. His wife preceded him in death.