District Judge Christina M. Habas entered the plea on behalf of 25-year-old Willie D. Clark, who is charged with first-degree murder and 38 other counts in the New Years Day 2007 slaying.
Habas denied the defense's requests to grant bail and a two-month delay, and scheduled the trial to begin July 6.
Williams and Clark were at a Denver club with separate groups that exchanged taunts before Williams and his friends left in a rented limousine, according to an October indictment. A witness told investigators that Clark was driving an SUV when he caught up with the limo and fired into it.
It took nearly two years for police to build their case against Clark.
A break came in August when police said they authenticated a letter in Clark's handwriting allegedly admitting to the slaying. The letter was obtained by the Rocky Mountain News.
During Friday's hearing, defense attorney Darren Cantor said Clark never told police he wrote the letter, only that it was in his handwriting. Cantor said the original letter was missing and that a copy obtained by police came from Clark's former cellmate, who had contacted the Denver Broncos hoping to collect a $100,000 reward.
Clark is a suspected gang member who faces murder charges in the unrelated shooting death of Kalonniann Clark in Denver in December 2006. The two were not related.
On Friday, Chief Deputy District Attorney Timothy Twining asked Judge Habas to take witness testimony in her chambers, saying that witnesses had contacted authorities "to express great fear."
The judge did not publicly rule on that request.