Bertrand Serlet, Apple’s senior vice president of Mac Software Engineering, will be leaving the company, according to an announcement released by the company today. Serlet worked with Steve Jobs at NeXT and came over with him to Apple, creating and developing Mac OS X. He will be succeeded by Craig Federighi, Apple’s vice president of Mac Software Engineering.

From Apple’s press release announcing Serlet’s departure:

“I’ve worked with Steve for 22 years and have had an incredible time developing products at both NeXT and Apple, but at this point, I want to focus less on products and more on science,” said Serlet.

Serlet famously poked fun at the similarities between Mac OS X and Microsoft’s then-upcoming OS update, Vista, at the WWDC Conference in 2006. His bit was more stand-up routine than keynote, made all the more charming by his thick French accent.

Serlet’s scheduled last day comes the day before Mac OS X turns 10 years old. Before joining Apple, he spent four years at Xerox PARC, then joined NeXT in 1989.