Sam Rockwell. Photo: Getty

Sam Rockwell looks like he’s having so much fun in The Way, Way Back that even the most withdrawn teenager in his orbit comes out of his shell. As the wise-cracking Owen, the manager of the Water Wizz water park (actually a real place), he sees a moping Duncan (played by The Killing’s Liam James) and puts him out of his misery — by giving him a job at the park, introducing him to everyone, and giving him choice tasks, i.e. ogling the girls in bikinis lined up for the water slide, breaking up a group break-dancers (who force him to dance with them first). It’s just enough to make you wish you had an Owen of your own growing up. Rockwell, who’s had his own share of odd jobs, chatted with Vulture about playing a crazy mentor, R-rated ad-libs, and his “shameless” dancing.

Bill Murray in Meatballs is the prototype for your character?

Yeah! It was pretty self-explanatory in the script. It was pretty obvious that this character was kind of an homage to that character, and some others: Walter Matthau from Bad News Bears, Richard Pryor in Bustin’ Loose. Those characters influenced me quite a bit, and Michael Keaton in Mr. Mom, and a little Night Shift. Those archetypes, the misanthrope, the grouchy adult that treats kids like adults. Bill Murray was the main go-to reference, and I think we talked about it a little bit, but it was sort of unsaid for me. But there are prototypes for every character, everything I’ve done. Everything’s been done before, you know? When I met Ron Howard for Frost/Nixon, I think one of the reasons I got the job is because I said, “Oh! You need Richard Dreyfuss in Jaws. You need Dustin Hoffman in All the President’s Men. That’s what you need here.” And I saw his eyes kind of light up, like, “Oh, yeah! This guy understands what I’m looking for.” It’s a quick kind of shorthand with filmmakers to reference films, because it’s part of the vocabulary. But you want to be careful — you don’t want to do a carbon copy of a carbon copy, you want to draw from real life. That’s why it’s important to watch documentaries and watch real people. When you’re playing a drunk, to research playing a drunk, you don’t get drunk. You go to a bar and you drink Coca-Cola and watch drunks, you know what I mean?

Did you have a backstory in mind for why Owen was stuck in this town or still working at a waterpark at this point in his life? He keeps referencing bits, so maybe he was a failed stand-up comedian?

You know, I never thought of that. But that’s entirely possible. The main thing was emotionally, he was masking a lot of vulnerability by always being on, always doing bits, keeping at bay any sort of feelings of vulnerability or intimacy with other people. I think that’s there in Bill Murray’s performance, too. Walter Mattheau in Bad News Bears, he’s a drunk. Billy Bob Thornton in Bad Santa, he’s a drunk. And he won’t let anything penetrate until the end of the film. They’re going to shoot him in the supermarket, and Billy Bob has this great moment of vulnerability, and you don’t earn that unless he’s done all this other stuff, by being the grouchy guy.

You were shooting at a real-life water park that was functioning at the time. Did that cause any difficulties?

There was a moment where I’m kind of embarrassing Duncan with a microphone, he’s trying to talk to a girl, and I was getting a little R-rated in some of my ad-libs, probably something about sexually transmitted diseases. I went a little too far, because I sort of forgot that there were kids there, and one of the women who worked there, one of the managers, came over and scolded us, “You got to get off the microphone, this is a place for families!” That whole thing. That was a sober moment for me, Uh-oh, we got to clean this up a little bit. The guys would always pull me back and make sure I was in the right place.

There are a couple of dance scenes, including when Duncan learns to break-dance and becomes known as Pop ‘n’ Lock. Did you chime in and teach him a few moves?

I stayed out of that one! [Laughs.] It was hard for me, but I stayed out of it. I hung out with some of the break-dancers, and they were cool kids, but I can’t do any of that shit anymore. I used to be able to do that, but not as good as those guys. Those guys were good. I can hoof it a little, but those guys are like gymnasts. Break-dancing has changed since I was a kid. You can’t just spin on your back anymore and strut around and undulate. It’s more like a gymnastic event.

Apparently you learned to do the dance-splits from watching Risky Business?

That’s right, that’s right. [Chuckles.] When I go to the gym, I stretch, I’m a pretty limber guy, but that’s kind of where I learned to do it, watching Risky Business over and over. That, and James Brown. In that one scene in the movie, I did a little hoofing, though. I’m shameless. I get a little carried away sometimes, but it was appropriate for that character. As long as it’s not inappropriate for the character. It seems to fit so far, but eventually, I’m going to get caught — like if I’m playing an accountant or something. Not that accountants can’t dance, but there will be some part where people say, “Take it easy with the fucking dancing, Rockwell.”

Even Justin Hammer [in Iron Man 2] could dance, though.

Justin Hammer had a little funk, but [Jon] Favreau egged me on to do that. I was sort of on the fence about that one. He’s an arms dealer, that guy. But we made him very flamboyant, so that was fun to work with, because we wanted a Lex Luthor kind of character.

Are you relieved that they didn’t kill Justin Hammer off, since it appears that was the original plan, according to recently released storyboards? Because you can come back, perhaps on Marvel’s Agents of S.H.I.E.L.D., with your pal Clark Gregg?

Ah! I was hoping to come back in one of the Avengers films and come after Gwyneth Paltrow, because that’s what they set up, that I was going to get revenge on Gwyneth for getting me arrested or something. I could do a Cape Fear thing with Gwyneth. But they’ve got a lot of mojo in there already, so I don’t know if they need another pirate like me in the mix there! [Laughs.] Maybe S.H.I.E.L.D. is the way to go.

Back to your dancing for a moment: Did you know there are Tumblrs dedicated to your dancing in films?

What was that? Tumblrs? What do you mean, Tumblrs? Somebody showed me a little bit of a montage from different flicks, and I thought that was pretty cool. Holy shit! Well, I would hope that Chris Walken has a website dedicated to his dancing, because he’s a hoofer. He’s a trained hoofer! James Brown is the real king. Awesome. I’m flattered! That’s really awesome.