Eich has also quit from the board of the Mozilla Foundation.
Mozilla’s recently appointed CEO, Brendan Eich has resigned in the wake of widespread criticism concerning his views on same-sex marriage.
Eich has also quit from the board of the Mozilla Foundation, the non-profit organisation that owns for-profit Mozilla Corporation.
In a company blog post, Mozilla executive chairwoman Mitchell Baker said the company prides itself on being held to a different standard.
"We know why people are hurt and angry, and they are right: it’s because we haven’t stayed true to ourselves," Baker said.
"We didn’t act like you’d expect Mozilla to act. We didn’t move fast enough to engage with people once the controversy started.
"We’re sorry. We must do better."
Eich confirmed the news on his personal blog, stating that he had left Mozilla in order to ‘take a rest’.
"I encourage all Mozillians to keep going," he said. "Firefox OS is even more daunting, and more important. Thanks indeed to all who have supported me, and to all my colleagues over the years, at Mozilla, in standards bodies, and at conferences around the world. I will be less visible online, but still around."
Eich reportedly donated $1,000 (£600) in 2008 for Californian anti-gay marriage law Proposition 8, while being initially passed the law was later tossed by the US Supreme Court in last year.
Dating site OkCupid also urged its users to stop using Mozilla’s Firefox browser in protest against anti-gay views of Mozilla’s new CEO and directed consumers to use other internet browsers, such as Chrome.
In addition, upon Eich’s promotion, app development firm Rarebit pulled its apps from Firefox browser.