Mozilla CEO John Lilly announces plans to leave

Mozilla CEO John Lilly has announced that he’s stepping down as soon as the company can find a replacement, in order to return to his first love, venture investment, with Greylock Partners.

“Venture investing is what I’ve wanted to do for quite a long time — I’ve been involved in many startups, even building an incubator a decade ago, and have interests that span enterprise, open source, and the broader web, among others,” he says.

“I’m incredibly excited to join an amazing team there, and the firm that I’ve noted to be incredibly strongly oriented towards entrepreneurs — it really matches my sensibilities as an operator quite well.”

Lilly joined Mozilla in 2005 and spent three years as chief operating officer before stepping up to the CEO position. He’s been notable for his outspoken opinions, publicly criticizing Apple for making Safari the default option for security update downloads and Microsoft for its browser option screen.

In a letter to employees yesterday, Lilly said he expected to be with the company for some months yet, and said he would stay on the Board of Directors. But, he says, he’s always been a start-up guy at heart.

In the meantime, Lilly says it’s business as usual. “We’ve got Firefox 4 to ship, and Firefox on multiple mobile platforms,” he says.

He also mentioned Weave, the company’s project to improve integration of desktop. The company released version 1.0 in January.

Mitchell Baker, chair of the Mozilla Foundation, said the timing of Lilly’s announcement was “to make this process more open than is generally the case and is a reflection of the uniqueness of Mozilla as a public benefit organization dedicated to openness and participation in internet life.”