Dennis Smith Jr. says he’s a different player than the last time he played in New York.

The Nets are counting on it.

In parts of three seasons with the Knicks following the trade that sent Kristaps Porzingis to the Mavericks in 2019, Smith played in just 58 games before he was sent to the G-League, where he was traded to Detroit in exchange for Derrick Rose.

Now, the 25-year-old is in Brooklyn, where the ninth-overall pick in the 2017 draft will be playing for his fifth different team in the past four seasons.

His time with the Knicks, Smith said, was transformative, even if it wasn’t successful.

According to Smith, he “checked his ego” while a Knick, specifically when he was sent to the G-League, which Smith added was his decision.

He was sent to the Pistons before even playing a game in the G-League, spent a season in Portland and then was productive for Charlotte last season before signing with the Nets this past offseason.

“It was a big mental shift,” Smith said. “[There’s] a lot that goes into being a professional basketball player other than just playing basketball. … The biggest thing for me was checking the ego. I learned how to shift my [mentality] into being able to fit whatever role I needed to play and find a way to stay in it. It’s paying off and I’m in a really good spot right now.”

And instead of the high-flying dunker he was when he left N.C. State, Smith now makes his presence felt on defense, which is what Nets head coach Jacque Vaughn is looking for from him.

“I love the juice, the energy he brings,” Vaughn said. “It’s contagious, the competitive nature.”

On what figures to be a mostly star-less roster, unless Ben Simmons can return to his former self, Vaughn and the Nets will be a defensive-minded team, which is fine with Smith.

“I’m going to compete,” Smith said. “I’m going to fight and I want to win games. I don’t want to lose. And I think that’s going to rub off on guys.”

He played with Dorian Finney-Smith in Dallas and said Finney-Smith “is the same way. We both bring that to the team, so you can’t help but follow suit.”

The key will be keeping Smith on the court.

The 54 games he played with Charlotte a year ago was the most Smith had played since his rookie season with the Mavericks, when he started 69 games and averaged 15.2 points per game, still a career-high.

But Vaughn said he won’t be asking Smith to focus on scoring.

“I think he is a tough-minded individual, which I love,” Vaughn said. “There’s some grit to him and some nastiness. We needed it.”

Those were not attributes coaches always would use to describe Smith’s game when he was a younger player who was known for his dunking prowess — despite being 6-foot-2.

Vaughn said jokingly that part of Smith is still there.

“He tried to dunk over somebody today [in practice], so he still has that, but he doesn’t mind the challenge of guarding anyone out there on the floor,” Vaughn said. “That mentality bleeds into confidence in other dudes around him on the floor.” 

And Smith insists he’s a more mature player than he was with the Knicks.

“Absolutely, but that comes with age,” Smith said. “The older you get, you’re supposed to learn. You’re never going to arrive. You just keep learning every day and keep growing, so it’s been paying off for me.”

His former Mavericks’ teammate, Finney-Smith, said his goal is to get Smith into the postseason for the first time.

“I’m happy he’s here, but we’ve got to get wins,” Finney-Smith said. “I’m happy my brother is here, but it would be even better to get him into the playoffs.”