Ryan Payton has resigned from his position as creative director at Halo studio 343 Industries.
He departs Microsoft’s Washington studio with the Halo 4 project one year away from its production deadline.
"I think time is the most valuable thing we have," he told Kotaku, "and I've decided that I'm not going to waste one more day working on something that doesn't speak to my values."
Payton had been diagnosed with “severe depression”, according to the Kotaku report.
"For somebody who loves this industry as much as I do and know how lucky I've been, I never thought I'd get to a point where I was so drained. That was when I knew I had to do something else."
Payton joined Microsoft from Konami in 2008, moving from Japan to the US due to personal matters. He departs from the Xbox company with a plan to establish his own independent studio, called Camouflaj.
“After a few years, there came a point where I wasn't creatively excited about the Halo project anymore,” he said.
"The Halo I wanted to build was fundamentally different and I don't think I had built enough credibility to see such a crazy endeavour through."
Halo 4, which begins the second Halo trilogy, is due for release in 2012.
The franchise has been Microsoft’s most successful ever in the games space, and is seen by Microsoft as a key driver for future software revenues.