Montee Ball was a Heisman Trophy finalist, an NCAA record-holder and an NFL second-round draft pick, and yet the running back’s promising career flamed out faster than Peyton Manning’s crawled to an end.

Three years after playing his last game with the Broncos, Ball has pinned his downfall on a dangerous bout of alcoholism that began during his junior year at Wisconsin.

“I started to drink a lot more and it started to pour into football,” Ball said in an extensive interview with SportingNews. “If I knew we had a super-easy practice the next day, I’d go out and get drunk with a whole bunch of people. I’d wake up drunk, hit the steam room and go to practice.”

His thirst for alcohol got so bad in the NFL, he said, he would get drunk up to four times a week. Playing for his favorite childhood team, the Broncos, didn’t help his focus when he would pay more attention to his phone than coaches, teammates and counselors.

“I wouldn’t take any of it seriously,” Ball said. “I was naïve enough to think my playing days would last forever. I would literally sit in the back of the room texting or being on Instagram not paying attention to the professional explaining to me about preparing for life after football and how important it is.

“I failed to use my platform to help others and to use the NFL as a steppingstone in life. I surrounded myself with bad people, not on the team but in the city. I was naïve enough to believe I had all the answers. I’m still kicking myself in the butt for that.”

Ball’s rebellious attitude seeped into almost every professional interaction, including when Broncos running backs coach Eric Studesville confronted him about his drinking problem.

“He talked about how he could smell the alcohol on me and that he thinks I may have a problem with drinking,” Ball said. “He said if I needed any help with that, he could reach out to people I could talk to. I didn’t listen to him.”

Ball, who said alcoholism runs in his family, found himself deep in legal trouble for other reasons last February, at which point the Patriots — the team most often willing to give troubled talents a second chance — released him from their practice squad.

Ball was arrested Feb. 5 on a felony battery charge and sentenced to 60 days in jail in August after two girlfriends came forward with separate accounts of assault. His girlfriend at the time of the arrest told police Ball had thrown her across a hotel room while at Wisconsin.

Ball, just 26, said he has committed to turning his life around since the birth of his son, Maverick, last year to a previous girlfriend, the “turning point” that showed him he has a “purpose.”

Now sober, Ball is back at Wisconsin — where he once broke the record for the most touchdowns in college football history — taking summer classes and attending counseling sessions. Ball said he is writing a book on coping with his alcoholism demons and dreams of opening a charity one day.

He remains an NFL free agent.