Marcus Jordan Says He's 40 Days Sober Months After DWI Arrest

Marcus Jordan appears to be making serious lifestyle changes following his recent legal troubles -- Michael's son says he celebrated 40 days of sobriety over the weekend ... months after he was arrested for DWI.

The 34-year-old former college basketball player shared the update on his Instagram Story on Sunday ... and it sure sounds like he's not turning back anytime soon, 'cause he's looking to add more days to that tally.

Jordan might be focusing on his wellness overall ... as he shared the news alongside a pic from inside a workout room.

It's a step in the right direction for Jordan ... as he stated in court docs back in March, he was struggling with "challenges" stemming from "alcohol/substance use" and offered to take courses to address the issues head-on.

As we previously reported, Jordan was charged with possession of ketamine, DUI with property damage, and resisting arrest after cops pulled up on his Lamborghini SUV on Feb. 4 stuck on train tracks in Florida.