Multerer, known as "Grey Matter" on Xbox Live, had been at Microsoft for nearly 18 years, starting off as an engineer with Microsoft's popular Web server before helping Microsoft become a big player in the video game market.
He was also involved in the design of Kinect, Xbox's TV services, managing a budget of 10's of millions of dollars, he says on LinkedIn.
Multerer announced his departure on Twitter on Monday:
Goodbye Microsoft. It was a good run. Xbox was Great! Time to do something new.