Kyrie Irving arrived in Brooklyn by owning his failure in Boston.

The Nets’ new star opened up Friday about his tenure with the Celtics and how the death of his grandfather impacted him. The heartbreak he went through as a person, he said, hurt him as a player. It also prompted him to reassess his priorities — and put coming home to family at the top of his list.

“After he passed, basketball was the last thing on my mind,” Irving said, as he was introduced at Nets Media Day. “A lot of basketball and the joy I had for it was sucked away from me, and it was a facial expression that I carried around with me throughout the year. Didn’t allow anyone to get close to me … and it really bothered me. I didn’t take the necessary steps to get counseling or therapy or anything to deal with someone that close to me dying.

“A lot of the battles I thought I could battle through in the team environment, I just wasn’t ready for. And I failed those guys in a sense that I didn’t give them everything I could have during that season. … My relationships with them personally were great, but in terms of me being a leader in that environment and bringing everyone together, I failed.”

Irving said that at the start of last season, he planned to re-sign with Boston. But two weeks later, on Oct. 23, 2018, his grandfather died. Irving — who already had lost his mother, Elizabeth, when he was 4 — fell into a depression that lasted much of the season.

The season saw Irving fuss with coaches and teammates, and ended with a second-round playoff loss to the Bucks. Afterward, Irving realized he needed family. He needed home.

“It started becoming more and more clear that my relationships within my home life have way higher precedence,” said Irving, who grew up in West Orange, N.J., as a Nets fan.

It was after playing at the Meadowlands during a fourth-grade school trip that Irving vowed he would play in the NBA. He remembers watching point guard Jason Kidd lead the Nets to consecutive NBA Finals.

The idea of getting to lead them back to that level and one step beyond — with father Drederick in the area and friend Kevin Durant on the team — was just what Irving wanted.

While many in Boston have doubted Irving’s leadership qualities, the Nets have praised them. Irving took charge of their offseason pickup games.

“You can see that on the court and off the court,” Rodions Kurucs said.

Joe Harris, who broke in with Irving in Cleveland, said his experience and maturation will naturally make him a better leader.

“He has a daughter, a family now. Those sort of things help on the court, too,” Harris said of the 27-year-old Irving. “As you adapt, have different life experiences, grow up, mature, that stuff translates to the court. It affects how you are as a leader.”

Irving’s familial instincts kick in when talking about Durant, suggesting the star was rushed back too quickly by the Warriors in the NBA Finals — in which he ruptured his Achilles tendon — and vowing to shield his friend from a repeat of that.

“I’m going to be the protector of that all throughout the year and not allow anyone to infiltrate that circle of ‘Hey K, do you. Get right. We’ll be fine,’ ” said Irving, who is relishing his return to the area — even if it means he can’t go out to a local park and shoot unnoticed.

“I popped up at a Brooklyn park not realizing that I’m still not normal,” Irving said.

“So when I go outside and I see all these kids leaving a bunch of courts, I’m like I just came here to shoot with my dad, because that’s where I grew up, outside playing basketball and having that attitude to really prove people right that I’m the next one meant to take over this league for the next few years.”