He sported his signature hat and denim was a staple for the line, a collaboration with G-Star and Bionic Yarn, which produces fabrics made by fibers collected from recycled plastic bottles.
"It's very easy to forget we live on this planet," Pharrell told the crowd. "We don't want to just talk about it, but we actually wanted to put it in practice."
The large room at 23 Wall Street was smoky and gloomy as lights beamed and ceiling featured a projection of artsy white spots. Frank Ocean and Jay Z's "Water" played in the background.
Pharrell, who has had huge success as a singer, rapper and producer, says he's always been interested in fashion.
"I have been given opportunities by really great companies, and I've been given opportunities by really great people," he said in an interview. "I wanted to learn more about what's out there creatively and how I could further find new ways to express myself."