Jean-Charles de Castelbajac is a 60-year-old French Marquis who designs clothes and listens to grime music. In the early 1970s, along with photographer Oliviero Toscani, he devised an advertising campaign blending sex and religious sloganeering that scandalized the Vatican.

A decade later, Castelbajac turned the Italian label Iceberg into a postmodern, pop-art fashion house, selling a bunch of hijacked Snoopy, Daffy Duck, and Felix the Cat imagery to Britain's football hooligans. In the 90s, he convinced the Pope and 5,000 priests to dress in what looked like hundreds of gay flags. More recently, a number of de Castelbajac's admirers, such as Bernhard Willhelm, Cassette Playa, and Jeremy Scott have themselves become well-known, reaffirming de Castelbajac's position as the king of cartoon couture.

When I met de Castelbajac inside his camouflaged neon Parisian store, he was negotiating a deal that would make him the creative director for a fireworks firm and was preparing to send off outfits for Beyonce and Lady Gaga's "Telephone" video.

Vice: Famously, you're a Marquis and not a fag, so why did you go into fashion?
Jean Charles de Castelbajac: My father was a piano player for the King of Morocco and my family had lost all their money. When you've spent years in a military boarding school, you want to meet girls more than anything. I tried being a singer in a band called Kaos and I tried acting in a couple of films, but I didn't like all the waiting around. I was in danger of becoming a small town art school flâneur, but then my mother asked me to design something, so I turned my old school blanket into a very austere jacket, and it eventually ended up being worn by John Lennon.

You were 18 and living in Paris in 1968. Do you think the politics of the time affected your work?
I wasn't so trendy in 1968. I was selling royalist fanzines when everyone was into Chairman Mao. But then one day I bumped into my godfather, a real socialist. He tore the fanzine out of my hand gave me a slap and shouted at me, "How can you dare?" He took me to see the students protesting at Le Sorbonne and the girls were much better-looking. This was the first time I saw lots of people wearing jeans and parkas in Paris. I couldn't leave the city after that.

Calling a sexy brand Jesus Jeans must have pissed people off. How did you convince people to go with it?
I was in my teens when I came up with the idea. My boss was a sort of visionary. He'd employed me when I knew nothing, because he wanted to do something new. We were in his Lamborghini and he was driving faster and faster, trying to scare me--there were no speed limits then--he was demanding, "Jean Charles, we have to find a way of making a lot of money quickly, but how?" I knew I had to come up with something right there, so I said, "We have to do jeans, they'll be a massive success, no one is making jeans in Italy." He hated my suggestion for a name at first, but then I said, "It has to be Jesus. It's the most famous name on earth." Soon, Oliviero Toscani and I were doing a massive campaign with girls' bums clad in the tiniest denim shorts, alongside biblical passages like, "He who loves me follows me."

Everything you do is so light-hearted. How do you avoid pressure from the business to get serious and move into traditional luxury goods?
I've always wanted to do socially dangerous things and fashion allowed me to do that. Fashion saved me. I have a strange pantheon of heroes for a fashion designer. Jimmy Page was my absolute idol and he did heroin, and I do what my heroes do. However, fashion saved me from being sucked into heroin because I knew that if I wanted to create revolutionary fashion, I needed to work. Fashion is my safety belt. That's why I love it so much. There's constant work and you have deadlines you can't miss. Friends in the business who got caught-up in the drugs and missed the deadlines actually died. Now fashion has gone corporate. When Claude Montana, Thierry Mugler and I first became successful, we were just excited to go to Rio on Concorde or see a huge crowd of yelling girls in Tokyo. We thought we were the Rolling Stones and we invested all our money in the shows--I'd have Grace Jones singing. It was a crazy and exciting time, but we didn't think about the business.

Does fashion mean you can mix danger with structure?
Risk is a big part of my creative life. When I first saw Malcolm McLaren's store, Too Fast To Live, To Young To Die in 1972, I felt like I'd finally found a brother-in-arms. Fashion is a manifesto for me. It's about asking questions. I don't care about wearability, I see fashion as a sort of warfare.

Seeing your Iceberg sweaters get taken up by the British working class must have been great.
Yes, and when I met the Slew Dem Crew I nearly cried because they knew my work so well. I always tell people about the time I met Dizzee Rascal and he could recount in detail the design of some of my Iceberg sweaters.

Everyone goes on about punk and Amazonian 80s power-dressing, but people forget that designers like Moschino and you were doing this whole pop-art, sloganeering thing.
When I think about my generation--Fiorucci, Moschino and even Thierry Mugler in a way--they were trying to say something with, not against, fashion. The pop-art and the fashion I identified with was a link to a beautiful window of shining happiness, but what people forget is that when I designed those Iceberg sweaters, all that brightness was linked to very dark electro music.

How did you get the priests to wear those rainbow flag-style vestments on World Youth Day in 1997?
Monsiuer Lustiger, a cardinal who was very close to Pope John Paul II, asked me to come up with something and we settled on the rainbow, because it represented God's promise of peace to Noah. When I told him the rainbow was also a gay flag he just said that no one had a copyright on rainbows.

Does liking fashion mean you're doomed to be a big kid forever?
No, I don't want to be a kid at all. There's a 16th century book I feel really close to called The Book of the Courtier by Baldassare Castiglione. His concept of Sprezzatura values generosity and reveling in the talents of others. I love that idea. However, lots of my friends are between 14 and 30. A connection to the sound of now is fundamental to me and will be until my last breath. Koudlam's dark apocalyptic electro means as much to me as the Yardbirds.

It was easy to attack society with your threads back when old people were scared of sex and fashion, but these days, outside, say, Saudi Arabia, can clothes still be controversial?
Good question. In France I'm still controversial, they think I make stupid cool stuff, they call it ridi-cool. How horrible is that? Fashion isn't about posing anymore, it's about performing and that can still be controversial. Fashion needs rebels. I think now a lot of the big fashion companies are desperate to have people who will do something powerful and rebellious with their brands.

So what makes good fashion?
Concept. I cannot make clothes or art or design without any concept. Fashion is a fantastic medium to tell stories, Gareth Pugh is brilliant at building his own world.

You've started making art too.
I feel like with my Triumph of the Sign exhibition, an artist was born, and now I didn't feel so schizophrenic. I have an atelier in China where they reproduce old masters and I paint stuff like the Red Cross, Nike, and Gucci symbols on them. Kanye bought three. With fashion, and now art, I've always had an obsession with merging things that don't go together. Outrageous and monstrous is beautiful.

That's great, but why did you do a fashion show with Lego?
The way Lego interconnects is a great metaphor for social networking. We took the idea to Lego, it wasn't the other way around, and the Lego Anna Wintour we did was just absurd. My next big fashion project is opening a pop-up shop in the basement of Selfridges called, An Encounter Of The 5th Kind. The 5th kind of encounter is when you and the alien have children. It's a sort of an anti-racist thing.