Five of his teammates logged more minutes.
And yet as you start to sort through all that went into Boston's 107-94 Game 2 win against Cleveland, you will be hard-pressed to find any Celtic whose play was more vital to the team's success than Smart who tallied a near double-double with 11 points and nine assists.
"Marcus always makes plays at the right time," said LeBron James. "He has a really uncanny ability to get into the lane and either creates for himself or create for others, and he did that tonight … he's always been very productive for their ball club."
Cavs head coach Tyronn Lue echoed similar sentiments about Smart.
"He makes winning plays," said Lue, a former Celtics assistant coach. "He makes tough plays. Like we said before, if it's 50/50 balls, he's going to get it. If it's a loose ball, offensive rebound they need to have, he's going to get it. We've got to be able to find someone who can match his toughness."
Good luck, coach.
Because Smart's toughness has been difficult to compete with, let alone match by any individual player or team.
And he displays that toughness at both ends of the floor, healthy or banged up.
In the second quarter, Smart was favoring his left knee at one point in the middle of a play. Moments later, he came up with a steal, limping at the time, that led to a Celtics lay-up.
And that doesn't even include him diving on the floor or into the stands, or standing up for a teammate who believes was being treated unfairly like the two-handed shove by J.R. Smith into Al Horford's back on a lob attempt.
Smart got in Smith's face and soon officials and players stepped in to separate the two before both were whistled for technical fouls and Smith's foul on Horford was upgraded to a flagrant-one.
"He's a true competitor," Brad Stevens said of Smart. "He matches his intensity with a physical toughness. People talk about him all the time. Sometimes they focus on things that don't matter, and the other times they focus on that he impacts winning. We are really glad he's on our team."
From an early age, Smart understood the best way for him to impact the game is bring a heightened level of toughness, regardless of who he's playing against.
So when told about Lue's comments about needing to find a Cleveland player to match Smart's toughness, "that's me," Smart said and then added, "That's how I was raised. I'm the youngest of four boys. My whole life I had to fight. I had to get down and do things in order to secure my spot in the household. So coming on to the court, it's nothing different."
Smart added, "we're the underdogs. We're coming in, Cleveland is picked to beat us. We've got to come and give energy, extraordinary energy all the time, and I just try to be that spark plug."