I first started exploring youth when I was young myself, with my Tulsa photographs [published as a book in 1971], ** and then it just became my thing. I knew that I wanted to make a film about teenagers. but by the time I was finally able to make one, I was much older. Most of my work had been autobiographical until then; I wanted to do something different. I had no idea what was going on with kids at the time, and I wanted to find out.

Visually speaking, I thought the most exciting kids were skateboarders, so I gravitated towards them. I met a skater in Washington Square Park [in downtown New York] named Tobin Yelland. I was teaching him photography, and asked him to walk me into his world. He introduced me to skaters and told them I was okay. And that was how it started—I hung out with skateboarders for about three years to get the story.

At the time, I was filming the skaters but I couldn't chase after them. I needed to be able to hold the camera and skate past them to film them. So I learned how to skateboard when I was 48 years old. It was a bit rough.

One day, Harmony Korine just sat down next to me in the park. He asked me about my Leica, and mentioned how much he liked Robert Frank. I thought it was odd that a kid would know about Robert Frank, so we started chatting. He told me he was in school and he wanted to be a screenwriter. About a year later, when I ready to make Kids, I thought, "Gee, I need a kid to write this." Harmony had written this 20-minute film in high school, and it was really good. I told him about the story I wanted to film, and he said, "I've been waiting all my life to write this." He was ready.

Harmony wrote the entire thing in a week. It was incredible. He had access to this world; he was one of them. I wanted the film to feel like you were eavesdropping on a secret world of kids that adults didn't know about, or access to. All kids have this secret world where they can be themselves. After a time, they let me in. They started telling me the truth about what was going on. I witnessed most of the things you saw in the film; the only part that was made up was when Jennie [Chloë Sevigny's character] gets AIDS. I needed that to tie the film together, for the story. Jennie was the maiden on the side of the railroad tracks. Otherwise it would've been like a documentary, and I didn't want to make a documentary.

I think Kids was so controversial because it was real. All the films I'd seen were goofs on what kids were doing or going through. Even the actors were older! I wanted to make a film about what was really going on, and use actors who were of the appropriate age. I cast amateur actors who were familiar with that world. I wanted to make it as truthful as possible.

When it premiered at Sundance in 1996, a lot of adults thought it was some crazy old man's fantasy. But all the kids said, "This is the way it is." There had never been a film made like it. I didn't think it was shocking. I just don't think people were ready for the truth. But now it's routine, it's all over the news. The film holds up well over time because I was just documenting life.

As told to Gillian Sagansky.