It took only a couple of years for Joseph Gordon-Levitt to start auditioning for parts, then break into the acting career that’s made him one of the busiest guys on the screen today. That’s no big deal except for the fact that he started those auditions, driven to them by his mom, when he was 6. Now 32, he’s built up quite an impressive résumé. He was already something of a veteran TV actor when he landed the part of Tommy, the wise old alien in a human child’s body on “3rd Rock from the Sun,” and has gone on to star in films including “(500) Days of Summer,” “Inception,” “The Dark Knight Rises” and “Looper.” But Gordon-Levitt, who also sings and plays guitar, is now complementing his acting chops by stepping behind the camera. He’s written and directed – and co-stars with Scarlett Johansson and Julianne Moore – in the new sex-porn-addiction comedy “Don Jon.” He recently spoke about breaking in, developing the new film and figuring out how to direct.

What got you interested in acting at such a young age?

I was born and raised in Los Angeles, and it was just one of the things I did. I played baseball and took piano and was in a choir. The music teacher who taught the choir started doing musical theater, and some of the kids in those classes were going on auditions. So I started going on auditions and really loved it.

You’ve been acting for a couple of decades. When did you first consider directing?

I think it always interested me. From the very first time I was on a set, it fascinated me to see so many people doing so many different, very specific things, all working together.

But wasn’t the idea of being the guy in charge a little daunting?

No, I didn’t think of it that way. An actor’s performance in a movie is not just made by the actor. So when I came up with the story for “Don Jon,” I didn’t want to just act in it. I had ideas for what I wanted the camera to do, what I wanted to do with the editing, what I wanted to do with the music. That’s why I wanted to direct the movie, so all those things could come together.

How did you learn to direct? Have you been taking notes on sets all these years?

I don’t know if I actually wrote down notes, but I was certainly paying a lot of attention. In 2011, the year leading up to shooting “Don Jon,” I got to work for three excellent directors: Rian Johnson on “Looper,” Christopher Nolan on “The Dark Knight Rises” and Steven Spielberg on “Lincoln.” They’re certainly all different filmmakers, but one thing I noticed that they had in common was they all have a really good balance between having a thorough plan but also being open to new ideas and spontaneity. That’s a balance that I think is right at the crux of being a director, because the decision you have to make all day long is “Do we stick to the plan or do we try this new thing?”

How did “Don Jon” actually come to be?

My earliest notes on it were from 2008. So in one form or another, I had this idea of a relationship between a young man who watches too much pornography and a young woman who watches too many romantic Hollywood movies. I obviously wasn’t writing it full time, but I’d always have new ideas about it. But in 2010, when I was in the middle of shooting “50/50,” I first conceived of it as a comedy. Once that clicked in, and I started picturing this version of a Don Juan character, and it started making me laugh, that’s when I really couldn’t stay away from it. So whenever I had a few spare hours, I would go back to it, write more notes, outline the story and think about how it would work.

A director really has to see the whole picture, and know what all the characters are thinking. Did you have to stop being the director while you were acting in the movie?

Sure, but I think what was really important was that I was so familiar with the material, because I had written it. I was way more familiar with this material than I was on any other acting job I’d ever done. Typically you spend a few months with a script, but this was for years. And I found that being in front of the camera, being in the scene, was the vantage point from which I could direct the best. That’s how I could gauge how it was going.

“Don Jon” opens on Sept. 27.

Ed Symkus covers movies for More Content Now.