Sam Rockwell, second from right, shakes hands with “The Way Way Back” co-star Steve Carell and apologizes for stealing every scene.

I expected Steve Carell to be the standout of “The Way Way Back,” which opens Friday. After all, he often uses film roles to remind us he can really, really act. It’s Sam Rockwell, though, as a manager at a seriously sketchy water park, who is the gleefully beating heart of the movie.

Rockwell may be this generation’s ultimate “Hey, It’s That Guy!” but he is so much more. He’s got some sort of special Rockwellian ingredient that makes every movie he’s in better.

“The Way Way Back” is a good movie he makes great. His appearance in “Iron Man 2” made a bad movie actually enjoyable for the short time he was on screen. In 2009’s very good “Moon,” he’s astounding as an astronaut slowly going bonkers. And “Galaxy Quest”! Oh, man, he was good in “Galaxy Quest,” wasn’t he? Hang on; I’m going to go read all the quotes IMDB has from “Galaxy Quest.” (“Guy, you have a last name.” “Do I? DO I?!”)

OK, I’m back. Originally, I was going to write about how “The Way Way Back” made me wonder why Rockwell isn’t a star. Now, though, I’m not sure I want him to be. A star is attractive and shiny and even useful at times, but in the end, there’s not much substance there. And yet we think of stardom as the pinnacle of an actor’s path; if you’re not caught pushing your kid on a swing in the “Stars! They’re just like us!” section of Us Weekly, then what does it matter how good you are at your craft?

So Sam Rockwell isn’t a star, and I get the impression that’s fine with him. What “The Way Way Back” proves yet AGAIN is that he’s an immensely talented actor capable of carrying a film. It wouldn’t hurt him to do a “Galaxy Quest” sequel, either.