For that, LeBron will have to win not just one championship. Not two, not three, not four...
It takes rings combined with MVP seasons to be considered the greatest of all time, and if you dispute that, you're disputing reality.
Whether he likes it or not, LeBron will always be compared to the likes of some of the greatest stars in the game—namely Kobe Bryant and Michael Jordan. After getting that first ring, which is likely to happen this season, the hunt will begin for more.
After all, James himself said he expected to win more. It's multiple or bust at this point, especially when you are as good as LeBron is on a team with two great players next to you in Dwayne Wade and Chris Bosh.
But you won't hear me faulting him for that or taking anything away from him for having those two players on his team.