The funeral was moved from Lowndes County to nearby Montgomery because there were no churches large enough to hold the expected crowd, a pastor told WSFA.
Monday's funeral was a mix of singing, tributes and memories of the 6-foot-4 sheriff lovingly known as "Big John," the television station reported.
Three Alabama sheriffs spoke during the service -- Cunningham, Clarke County Sheriff Ray Norris and Russell County Sheriff Heath Taylor, AL.com reported.
"Nobody ever questioned John's integrity," Taylor, who is president of the Alabama Sheriffs Association, told the crowd. "He always stood on the side of what was right. He was a man of honor and pride and respect for others. Nothing made him happier than helping somebody in Lowndes County."
After the two-hour service, Williams' body was taken to the Original Shiloh Primitive Baptist Church cemetery in Hayneville, where the sheriff served as a deacon.
The service ended with a final dispatch call to the sheriff recorded for the occasion, AL.com reported.
“We thank you for your dedication, loyalty and service to the citizens of Lowndes County, Alabama and to the United States of America. ... Rest in peace ... end of watch.”