"Good reason does not exist to keep the record of this case sealed," wrote Cook County Circuit Judge Steven Watkins.
Police superintendent Eddie Johnson and then Mayor Rahm Emanuel condemned the decision.
Defense lawyer Patricia Brown Holmes lied about the dismissal and told reporters that prosecutors were trying to seal the case.
However, Thursday's order says that Smollett's defense team requested that the files be sealed and prosecutors not protested. Writing that it is "easily conceivable that a defendant whose case was dismissed wants to maintain his sense of privacy," Watkins said that this was not the case with Smollett and noted the actor and his lawyers spoke to more media after the dismissal.
"These are not actions of a person seeking to maintain their privacy or just being abandoned," the judge said. "While the court appreciates that the defendant was in the public eye before the events that precipitated this case, it was not necessary for him to treat this so publicly and to such an extent."
CNN was among many media struggling against the archives sealed It is unclear when the documents will be available to the public.
Smollett's publisher, Hilary Rosen, declined to comment on the ruling.
CNN's Eliott C. McLaughlin wrote and reported from Atlanta, and Brad Parks reported from Chicago.