Kenny Anderson in a scene from his new documentary "Mr....

Kenny Anderson in a scene from his new documentary "Mr. Chibbs." Credit: BMG Brokers

Kenny Anderson is a grandfather, which comes as a shock if you are someone who began writing about him when he was, gulp ... 15.

But so it is.

The most celebrated New York high school guard of the late 20th century is 46 and more than mere years removed from his glory days.

Some of those years have been hard ones, and Anderson wants to share his experience in hopes of easing the path of future young stars, and of young people in general.

That was why he participated in an unsparing documentary, “Mr. Chibbs,” (his childhood nickname), which premieres on Nov. 12 at the DOC NYC festival in Manhattan.

Anderson said he shared writer/director/producer Jill Campbell’s approach, which was to minimize basketball and focus more on life.

“I think it was therapeutic for me, having a crisis in my life, trying to find myself after retirement,” he said. “I thought it would be great to get my story out to help others. We had the same vision.

“I could have gotten with any big-time director and maybe they would have seen something different, made it more about basketball. But this is my life story. Anyone can do highlights and a basketball reel.”

Anderson is an unusual case in the fallen-sports-star canon.

After leaving Archbishop Molloy High School in Queens, he led Georgia Tech to a Final Four, was the second player taken in the 1991 NBA Draft — by the Nets — was an All-Star in 1994 and spent 14 years in the league. So he hardly was a bust.

And yet, he never fully realized his potential on the court, while undermining himself off it with money mismanagement, alcohol abuse and a complex romantic life that has produced eight children — seven of them biological, one as a stepfather — with five women, as well as three marriages.

“Mr. Chibbs” finds him in the middle of a couple of unfortunate episodes.

In 2013, he lost a job he cherished coaching at David Posnack Jewish Day School in Davie, Florida, after a DUI arrest.

In 2014, he joined Dennis Rodman on a bizarre trip to play in front of North Korean leader Kim Jong Un.

Anderson reflects emotionally and candidly on those and many other topics, including the sexual abuse he endured in his early youth and his close relationship with his mother, Joan, who had troubles of her own before her death in 2005.

“I thought it was great; I enjoyed it,” he said of the film. “That’s the basic story, but there’s no ending. We’re all a work in progress. At the same time I’m working and trying to do better for myself and my family.”

Anderson acknowledged it was difficult to open up on film.

“I could have just talked about all my highlights and it’s peachy cream, but my life hasn’t been peachy cream,” he said. “I’m letting the world and all my fans understand I’m trying to find myself after being molested at an early age and having to hide it, not knowing how to come out because I had fame at an early age and didn’t want to be embarrassed.

“That was big for me. That was huge, because I held it in for 30-something years ... It want to help other kids that have been abused and molested. I know it’s out there.”

Anderson largely credited his children’s mothers for the people they have become.

“I tell my sons, it’s a blessing I have kids, but I would have liked to do it a better way where I could be there all the time in their lives,” he said. “I was on the road in the NBA. And No. 2, when you have babies out of wedlock things don’t happen the way you want them to happen. You’re not with that woman. So you’re away from your kids. That’s difficult.”

Anderson long has had a passion for coaching and teaching, and his biggest current project is a gym in Tampa called The Clinic. He plans to start with high school players and eventually train elite, potentially NBA-bound college players.

His name is not much of a draw initially with young athletes, but their parents tip them off, which leads to Google.

“Then they’re like, ‘Wow, it’s Kenny Anderson,’” he said. “But I want them to respect me not only in what I do with the basketball. I try to get into their heads and mentor them. It’s easy for me to teach them the crossover, pullup jump shots, ballhandling.

“But it’s even better to try to mold them and help them in life, whatever they’re going through to try to teach them some of my life lessons. It’s all about paying forward.

“I’ve been losing a lot of my closest friends through death. If I leave this earth just having accolades for playing basketball, that’s nothing. I have to leave a legacy that when I leave here, how many people did I help along the way to leave something?

“I hope I raise a bunch of those guys with Division I scholarships and go onto the pros, but if I do [help] one kid and he goes off and has a great college career and a great life and learns from some of my mistakes, I’m like hey, I did good.”