Open source software provider Mozilla’s co-founder and new CEO Brendan Eich has stepped down from his role just eleven days after taking it on. Eich was appointed CEO last Monday but the firm announced his resignation yesterday following backlash from Mozilla’s developer community over donations Eich made to an anti-gay marriage lobbying effort in California six years ago.

Shortly after Eich’s appointment last week the firm posted a blog entry clarifying its “official support and inclusion of LGBT people” but it was not enough to quiet the objections.

This week the firm issued a follow-up statement in which it apologised for not having “stayed true” to itself. “We didn’t act like you’d expect Mozilla to act,” it said. “We didn’t move fast enough to engage with people once the controversy started. We’re sorry. We must do better.

Announcing Eich’s resignation, Mozilla executive chairwoman Mitchell Baker said that Eich made his decision for Mozilla as well as its developer community. She added that plans for the firm’s leadership are currently under discussion.

Eich has been a central figure at the firm since its creation in 1998. Prior to taking on the role of CEO, he had served as chief technology officer at Mozilla and he has been widely credited as the creator of programming language JavaScript.

In April 2013 Mozilla announced that former CEO Gary Kovacs would be stepping down from his role later that year and that it would immediately begin its search for his successor. After Kovacs left the firm, COO Jay Sullivan was appointed as interim CEO before Eich’s appointment last week.