The singer-songwriter - who worked closely with Massive Attack - was found dead at his home on Sunday (October 28), reports the Chicago Sun-Times.
The musician's 50-year-long career began in 1962 when he signed to Chess Records in the United States.
A trio of Callier's records - 1972's Occasional Rain, 1973's What Color Is Love and 1974's I Just Can't Help Myself - helped propel him to critical acclaim from his peers.
After quitting music to study computer programming in the 1980s, Callier accumulated a cult following in the UK and is often cited as an inspiration for modern-day singer-songwriters, including Michael Kiwanuka.
Callier's final album - 2009's Hidden Conversations - saw him continue his work with Massive Attack.