The former "Empire" actor's appeal argued that a special prosecutor should not have been allowed to intervene after the Cook County state's attorney initially dropped charges. The state's highest court heard arguments in September.
The court said in its ruling, "We are aware that this case has generated significant public interest and that many people were dissatisfied with the resolution of the original case and believed it to be unjust. Nevertheless, what would be more unjust than the resolution of any one criminal case would be a holding from this court that the State was not bound to honor agreements upon which people have detrimentally relied."
In its ruling, the Illinois Supreme Court referred to the Bill Cosby case in Pennsylvania in making its decision.
"As the Supreme Court of Pennsylvania recently stated when enforcing a prosecutorial promise not to prosecute, 'It cannot be gainsaid that society holds a strong interest in the prosecution of crimes. It is also true that no such interest, however important, ever can eclipse society's interest in ensuring that the constitutional rights of the people are vindicated. Society's interest in prosecution does not displace the remedy due to constitutionally aggrieved persons.' Cosby, 252 A.2d at 1147."
Smollett, who is Black and gay, claimed two men assaulted him, spouted racial and homophobic slurs and tossed a noose around his neck, leading to a massive search for suspects by Chicago police detectives and kicking up an international uproar. Smollett was on the television drama "Empire," which filmed in Chicago, and prosecutors alleged he staged the attack because he was unhappy with the studio's response to hate mail he received.
A jury convicted him of five counts of disorderly conduct in 2021. Smollett has maintained his innocence.
His attorneys appealed that conviction, arguing that he should not have been punished for the same crime twice.
In December, an Illinois appeals court upheld Smollett's disorderly conduct conviction, and Smollett turned to the state's highest court soon after. The appeals court voted 2-1 in favor of upholding the conviction.
Back in 2019, he and Cook County State's Attorney Kim Foxx had reached an agreement to drop the charges against him in exchange for $10,000 bond and community service. A special prosecutor was then appointed in 2020.
Smollett's lawyers claimed his conviction violated his fifth amendment rights against double jeopardy, which is a legal protection against a person being punished for the same crime twice.
The special prosecutor disagreed with their premise, arguing that Smollett did get due process and was never prosecuted in the 2019 case, adding that the agreement for his release included an understanding that he could be re-charged for the original crime.
Smollett's attorneys added that the special prosecutor, who they say never should've been appointed, also did not turn over important evidence to the defense team from an hour's long discussion with the Osundairo brothers, Abimbola and Olabinjo.
The Associated Press contributed to this report.