Smart explained when LeBron was at his best as a player.
2012 N.B.A. Finals — James Lives, Learns and Just Might Win - The New York Times

Marcus Smart faced LeBron James many times throughout his career. When he was still a member of the Boston Celtics, they clashed with LeBron thrice in four postseasons but failed to beat his Cleveland Cavaliers each time.

Smart witnessed arguably the best version of LeBron in 2018 when the superstar forward single-handedly led the Cavs to their fourth-straight Finals appearance. But despite this, he still thinks the Miami Heat’s LeBron was an even better player.

“Imma go ’12. ’18 didn’t do him no justice. I don’t mean that against him, but it’s just that he didn’t had a squad,” Smart said in his appearance on the Run Your Race podcast. “You know what I’m saying? He didn’t really, and at that time, everybody’s expecting him without the squad even though he didn’t have [a chance] to steal. That’s why.”

2012 vs. 2018 LeBron

The 2012 James had no flaws in his game. At age 27, he enjoyed the pinnacle of his physical state and could do it all—The King was engaged on both ends of the floor, scoring, playmaking, rebounding, and defending. Once he received the ball in transition, there was nothing opposing teams could do as LBJ was always running at full steam with his immense power and motor.
LeBron James beats Celtics, leads Cavs to 2018 NBA Finals.
That said, the 2018 version is arguably LeBron’s offensive apex. Although his athleticism slightly dropped, he was much more mature and wiser in his decision-making. The then-Cavs superstar fully embraced the leadership role and already had tons of basketball experience. At that time, he was also a great three-point shooter who could hurt his opponents from anywhere on the floor.

Playing alongside Dwyane Wade, Chris Bosh, and some great role players, LeBron had a great supporting cast that helped him win his first championship in 2012. But in 2018, he was carrying the Cleveland squad on his own, which was even more impressive in Smart’s eyes.

Two of Bron’s best versions

Regardless of the comparisons, 2012 and 2018 were the best individual years LeBron ever had, which is a testament to his unmatched longevity and sustained basketball excellence. Most all-time greats have enjoyed a single prime throughout their career, but LeBron has separated himself by being consistently great since entering the NBA in 2003.

James is still great, having averaged 25.7 points, 8.3 assists, 7.3 assists, and a career-best 41.0% from the three-point line in the 2023-24 season for the Los Angeles Lakers. He’s not the defender he used to be, but regardless, The King continues to showcase unprecedented greatness, especially for a guy his age.