The actor went into court Monday in NYC with his attorney and his girlfriend, Meagan Good, by his side. He looked solemn and serious, and didn't stop for questions. A judge sentenced him to a one-year intervention program that'll be completed in L.A.

As part of his program, he'll have to do 12 months of counseling ... one session per week over the course of 52 weeks. The D.A.'s office says if he doesn't comply with the conditions set here, he could face time behind bars.

Jonathan was facing up to one year behind bars after being accused of roughing up his ex-girlfriend, Grace Jabbari, and being convicted on 2 of 4 counts ... assault and harassment. He was acquitted on two other counts of assault and harassment.

Remember ... Jonathan was found guilty after about a two-week trial -- this after a number of witnesses testified as to what happened in March 2023 ... when he was alleged to have physically harmed Jabbari in the back of a rideshare on their way home.

Surveillance footage from that night was played in court -- and while whatever happened in the car was never seen .... jurors were able to view what happened outside of the vehicle.

Majors was seen trying to escape Jabbari ... and at one, point put her back in the car before she gave chase down the street. She eventually ran into a group of people that she went out with afterward -- something Majors' team argued proved she wasn't harmed whatsoever.

The next morning ... Jabbari turned up at their shared home, and she appeared to have injuries on herself -- which she ultimately attributed to Majors. While Majors insisted he didn't lay a finger on her that night ... the jury convicted him.

While he tried having that conviction tossed, a judge ruled that the charges would stand.

The guilty verdict has already cost Jonathan big time ... he's been booted from a bunch of Hollywood projects, including his most lucrative role with Marvel, Kang the Conqueror.

For his part, Jonathan maintained his innocence in an interview with ABC News ... his first since the verdict ... though he expressed regret over how he handled things with Jabbari.

Leading up to his sentencing, Jonathan was staying positive ... telling us he was relying on faith and prayer for some light in a dark time in his life. We've also seen him out a lot in L.A. in the aftermath -- even hitting up public events and smiling for cameras.

Jon has told us he's focusing on new projects on the horizon -- and hasn't seemed too worried about the prospect of going to jail. Even after Jabbari sued him over all this ... he wasn't all that concerned.

Now, he can put this saga behind him ... at least on the criminal side.