Williams died Sunday at the University of Texas M.D. Anderson Cancer Center in Houston, said JoAnn Geffen, a spokeswoman for the band.
Williams, who played keyboards, was one of the founding members for the Commodores, which formed in 1968 while all the members were in college at the Tuskegee Institute in Alabama. The group, whose best known member was singer Lionel Richie, had a series of hits during the 1970s and 1980s, including "Brick House," "Easy" and "Three Times A Lady." Williams wrote the band's first hit, "Machine Gun."
"He was once, twice, three times a brother and we love him. He gave all that he could give to the Commodores. He'll always be remembered," said band member Walter Orange.
He is survived by his wife, Melanie Bruno-Williams, and two sons from previous marriages, Jason and Ricci. The funeral will be on Friday in Okolona, Miss., where Williams was born. There will be a memorial service in Los Angeles in August.