The actor just scored a huge W Wednesday -- 'cause the Supreme Court of Illinois ticked his case off as one they are open to hearing ... in other words, his appeal to the State Supreme Court is approved, and the justices for this court will weigh in on this saga once and for all.

Remember, Jussie has been appealing his conviction pretty much ever since it came down way back in 2021 ... when a jury found him guilty of lying to cops about a hate crime he claimed he'd been victim to.

Jussie was defiant after the verdict came in -- and while he was sentenced to 150 days in jail ... JS only served 6 days behind bars before he was sprung as his appeal worked its way through the court system.

There were some ups and downs before this big decision ... as we reported, he was handed a loss in an Illinois appeals court when he first asked them to look over the case, with a 3-judge panel upholding the conviction and finding that the jury was justified in their decision.

Of course ... Jussie appealed that decision, throwing a Hail Mary in hopes that the Illinois Supreme Court would hear him out -- and now, they've signaled they're willing to do that.

You'll recall ... Jussie's whole argument here on why his conviction should be tossed is based on his claim that he had a deal with the prosecutors who were first handling his case, which he says explicitly stated he wouldn't be prosecuted if he signed up for their terms.

At the time, all Jussie was asked to do was forfeit a bond he'd paid ... and do community service -- and he says he's upheld his end of that bargain. Afterward, though, a special prosecutor came aboard and put him under the gun again ... which Jussie calls BS.

The special prosecutor, however, said the deal Jussie thought he'd struck with the previous team did not, in fact, protect him from further charges ... and he also argued double jeopardy doesn't apply in this case. It's all very technical, but the special prosecutor was asking the State Supreme Court to reject his bid.