But playing a supporting role in a movie? That's another matter.
"It's different than walking on the NBA floor, I'll tell you that," he told Rachel Nichols of CNN Sports. "I had much bigger nerves walking on set. It's my first time. I've done commercials, I've done PSAs (public service announcements). I've done so many great things, but I've never stepped on a movie set. But it was extremely fun to be around those guys."
James makes his acting debut in the comedy "Trainwreck," directed by Judd Apatow and written by Amy Schumer. The movie hits theaters Thursday night. James plays himself, and he is cast as the best friend of actor Bill Hader's character, sports doctor Aaron Conners.
And his role isn't just a cameo. It became much more than that.
"Judd Apatow is one of the greatest directors and writers that we have," James said. "I had a few scenes that we were going to do -- a couple scenes, not a few. I had a couple scenes -- and myself and Bill Hader, we kind of just hit it off, right off the bat.
"And it was, like, 'OK, well, you know, you mind sticking around for a couple more days? We're going to write another scene in here.' And then I got into a scene with Amy Schumer, who's unbelievable. And it was, like, 'You mind sticking around for just one or two more days?' And I ended up doing, like, five or six, maybe, like, seven scenes. I don't want to give it up, how many scenes I'm in."
In the NBA Finals against the Golden State Warriors, James put the Cleveland Cavaliers on his back, averaging 35.8 points, 13.3 rebounds and 8.8 assists per game -- leading both teams in those categories. His injury-depleted Cavaliers ultimately lost to the Warriors in six games, but James single-handedly kept the series closer than most anticipated.
But in addition to hoops, James also is interested in taking his talents to the big screen.
"I always talked about it as a kid," he said. "And even as an adult, I was, like, 'Wow.' You know, I always wanted to be the Fresh Prince of Bel-Air," he added, referring to the 1990s sitcom. "Will Smith kind of set it up. I was, like, 'Man, that would be cool to be the Fresh Prince of Bel-Air. How amazing would that be? Just be a silly kid in an unbelievable house and be around so many great people.'
"And then when I got older, you know, the 'Bad Boy' movies, I was, like, I would love to do an action movie -- you know, be like a cop or something or be like Batman and be a superhero and be able to save people and save corruption and all that mess. I've always had it in my head."
The NBA superstar known as the The King looked like he could be a natural in comedic acting as well, as evidenced in a "Trainwreck" trailer. Critics say
that James' acting is the real deal.
A sample from the trailer
James, entering Conners' office: Sorry to interrupt. Are you watching "Downton Abbey" later?
Conners: LeBron, I'm being interviewed.
James: Listen, I'm watching it tonight, because I'm not going to go to practice and all the guys are talking about it, and I'm left out.
From the way James talks, this sounds like it may not be his last movie. He says he hopes he can do some more acting work.
"So goal number one, win an NBA championship for Cleveland," Nichols said.
"Absolutely," James replied.
"Down the road, goal number two: Be Batman and save the world?" Nichols asked.
"Yeah, yeah," James answered with a laugh. "Not bad at all."