Balancing emotion and composure is a constant struggle for Marcus Smart. Sometimes, that fire for success on the court can erupt, but on every level it has been the driving force in making him a vital part of a team.

Ask Boston Celtics management and coaches, and it’s clear Smart’s intangibles and passion help foster victories. Around the NBA, team executives agree with Celtics head coach Brad Stevens’ observation: “Marcus impacts winning.” The Celtics are hitting their stride now as the All-Star break nears, and Smart and Jae Crowder, a budding all-around player, are leaders of the team’s scrappy, win-at-all-cost style.

So when Smart hears criticism about his shooting ability, he nods. He knows that wins serve as the remedy in Boston, and he controls the facets of the game that are instinctive. From the moment the Celtics drafted the point guard with the sixth overall pick in 2014, Smart’s defensive intensity afforded him minutes despite a developing jump shot. This season, Smart is the only player from his draft class averaging 30 minutes or more on a playoff team (30.7).

He’s still grasping pick-and-roll play and the balance of shooting and passing, but gives Stevens versatility. The emotional component is being honed now, but it has been a struggle since his Oklahoma State days.

“I’m harder on myself than anybody can ever be on me,” Smart told The Vertical. “I’m my biggest critic besides my parents and the people that love me. I hold myself to a different level, so when I feel like I could’ve done much more or I didn’t play to that level, I can let my emotions get the best of me.

“When I use my will and determination, my emotion comes in.”

So often, Boston incorporates Smart’s vigor and tenacity into their collective play. Isaiah Thomas and Al Horford are the leaders with All-Star pedigrees, and they understand more than anyone how much Smart means to the team. Smart lost his older brother, Todd, in 2004 and that fuels his values of brotherhood and relentlessness.

“Losing my brother and dealing with everything life has thrown at me,” Smart told The Vertical, “it taught me that I would do anything for these guys in the locker room, from the coaching staff to the trainers to the players.”

That was apparent in the Celtics’ loss to the Washington Wizards on Jan. 24, when Smart had an animated exchange with members of the coaching staff. The Celtics and Wizards have developed a little rivalry while contending for second seed in the Eastern Conference behind Cleveland, and Smart had taken the game personally. Late in the fourth, Bradley Beal scored an and-one basket against Smart and flexed his arms, leading to Stevens removing Smart.

The game’s impending outcome had irritated Smart above all, and sure, Boston could have suspended or fined him for the bench incident. Instead, Stevens observed Smart apologize to each player and coach in the postgame locker room. Smart understood immediately his emotions got the best of him, and he showed remorse and accepted responsibility. Stevens had a brief talk with Smart the next morning, moved on and both sides believe the relationship strengthened in the weeks to follow.

“I knew what I had done in the moment and it happened so fast,” Smart told The Vertical. “My feelings were already out there. I couldn’t just be like, ‘Oops, I take it back.’ It happened, you go through it and I dealt with what came after. That’s what the NBA has shown me, being professional and owning up to it. Whatever consequences, whether it was a suspension or not, I would’ve taken it and still cheered my team on.

“Everyone on this team understands the type of player I am. I mean no harm. I’m just an emotional dude who likes to win.”

Before the postseason, the Celtics hope for the continued development of Smart, who’s averaging 10 points and 4.7 assists, and will pursue the acquisition of a center. They worked out former Milwaukee Buck Larry Sanders last month and have had preliminary discussions about several big men on the trade market, sources told The Vertical. Within the locker room, the belief remains that Boston must improve from within. For Smart, it begins with the message his closest friends emphasize: consistency.

“Each and every day, I want to be more consistent,” Smart told The Vertical. “I feel I’ve always been a point guard and I feel I can see the court and make plays for others. But this is my chance to learn [the] pick-and-roll game, seeing the floor in transition.

“At the end of the day, I know what I’m capable of. I just try to want it more than the other guy that I’m playing against. It’s a key factor in the way I play, the way I get my edge.”

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