A teenage boy pleaded guilty Tuesday to murder for his role in the December 2019 stabbing of Barnard College student Tessa Majors.

Luchiano Lewis, 16, pleaded guilty to second-degree murder and first-degree robbery nearly two years after Majors’ tragic killing inside Morningside Park.

Manhattan prosecutors charged Lewis as an adult. He has been in jail since February 2020.

Lewis told Manhattan Supreme Court Judge Thomas Farber he didn’t know Majors had been “stabbed let alone killed” during the robbery until he read it in the news the next day.

The teen said he and two school friends — Rashaun Weaver and a 13-year-old who pleaded guilty to robbery as a minor — had plans to rob someone inside Morningside Park on December 11, 2019.

After their first attempt on a man failed, the group targeted Majors, Lewis said, who was jogging down a set of steps in the park on W. 116th St. near Morningside Drive.

“She had just walked up the long set of stairs and was walking toward us, but she was looking down at her phone. We were walking on the right side with the rails. When she passed us on our left, I saw Rashaun whisper something to (the 13-year-old), but I couldn’t hear what he said,” said Lewis, stuttering throughout his lengthy statement to the court.

“Rashaun turned around, ran up behind Tessa Majors and kicked her hard in the back. I watched her stumble. Rashaun started screaming, ‘Give me your money, run your pockets, I’m not playing.’”

The teen said Weaver, who has pleaded not guilty to murder, “tussled” on the steps with Majors for some time before Lewis became spooked by an onlooker. They all fled the scene.

“I do not know exactly where the three of us were when Rashaun stabbed Tessa Majors because he tussled with her in two different places: near the tree when we first saw her and then again at the bottom of the big stairs that go back and forth, but at one point, I did see feathers coming out of her jacket when we were at the bottom of the big stairs that go back and forth. I know that Rashaun had a knife that night,” Lewis said in court, seated feet away from Majors family members, who traveled from Virginia to attend the hearing.

“Once we were out of the Park, I asked Rashaun several times, ‘What did you get?’ He just kept saying, ‘Nothing.’ After we started walking, Rashaun showed me his hand and said, ‘The bitch bit me.’ We walked together for a little longer. When I left them to go home, Rashaun and (the 13-year-old) were still together. At that point, I did not know that Tessa Majors had been stabbed, let alone killed.”

The random killing of the young student put the Columbia University campus and neighboring Harlem community on edge. At the youngest suspect’s sentencing last year, Majors’ parents, Inman and Christy Majors, told the court in a letter of their unimaginable pain and grief in losing their daughter.

“On Labor Day weekend 2019, the parents of Tess Majors dropped her off at Barnard College in New York City to begin her freshman year of college. One hundred days later, they brought her home to Virginia in an urn,” the statement read.

“What words could be used to describe that grief? Compounding the sudden loss of their talented, kind, and beloved daughter, sister, granddaughter, great-granddaughter, cousin, and niece is the incredibly violent nature of her death, which has been described in grisly detail by the respondent himself.”

Majors’ parents declined comment at Lewis’ plea hearing. They will read a statement at his October 14 sentencing.