He died in a Bradenton, Fla., hotel after being ill for about a month, the Bradenton Herald reported Tuesday.
There was no evidence of foul play, said Dave Bristow, a spokesman for the Manatee County sheriff's office. An autopsy will be conducted.
Williams' mother, Ozepher Fluker, said he told her he had not been able to taste anything and had experienced stomach pain for about a month. She advised him Friday to go to the hospital, but never heard from him again. Deputies found him dead Monday.
Williams lived on the streets of Bradenton and Miami after his grandmother died in 1993. He moved back to Bradenton and got an apartment to finish high school so he could fulfill a pledge to his grandmother. Williams worked at a grocery store after school to pay his bills, former Florida State University coach Bobby Bowden wrote in his memoir.
Williams played football in high school and at FSU, where he helped the team win a national championship. After earning a degree in sociology and criminology, he was signed by the Tennessee Titans.
At the time of his death, he was a teacher at Manatee Y Technological High School.
His mother said Williams had lived at the hotel about six years.