Willie Clark was convicted of first-degree murder in the New Year's Day 2007 drive-by slaying of Williams.
Before he was sentenced, Clark was declared a habitual criminal, making him eligible for the 1,152 years in prison.
Clark, who had two prior felony convictions, also was convicted of 16 counts of attempted first-degree murder and aggravated assault in the Williams case.
Rosalind Williams called her son's slaying a cowardly act and said gang violence must be stopped. "Now, when anybody says Happy Mother's Day, it hurts, because my baby will never be able to tell me Happy Mother's Day again," Williams said.
Defense attorney Darren Cantor had asked District Court Judge Christina Habas to excuse Clark from hearing Williams' mother address the court. Habas refused.
Witnesses during the trial testified that Clark desperately searched for a gun following an altercation at a nightclub, hopped into an SUV to catch up with a limousine carrying Williams, then fired the fatal shots.
Clark also exchanged words with then-Broncos wide receiver Brandon Marshall as Williams arrived at the nightclub with a group. The confrontation escalated inside when somebody in Williams' group sprayed champagne in celebration.
The dispute continued outside as Williams and his group tried to leave, and ended in gunfire a few blocks away.
Prosecutors portrayed Williams as a peacemaker as his friends argued with gang members who had taken exception to the special treatment afforded the celebrated athletes.
Several witnesses testified they saw or heard from Clark that he fired shots from an SUV into a stretch Hummer limousine carrying Williams and 16 others from the nightclub shortly after 2 a.m. Williams died in teammate Javon Walker's arms.