Bertrand Serlet speaking on stage at Apple&39's Worldwide Developer Conference in 2009.

Apple's senior vice president of Mac software engineering, Bertrand Serlet, is leaving the company.

Known for his role in creating and developing the Mac OS X software, Serlet will hand over the reins of his job to Craig Federighi, currently the vice president of Mac software engineering, Apple announced today.

Federighi, who will report directly to CEO Steve Jobs, has been responsible for the development of Mac OS X and has managed the Mac OS software engineering group the past couple of years.

"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," Serlet said in a statement. "Craig has done a great job managing the Mac OS team for the past two years, Lion is a great release and the transition should be seamless."

Seen as a key contributor to the design and development of Mac OS X, Selert has been a vocal champion of Apple's operating system. In his keynote speech at the 2009 Worldwide Developer Conference, for instance, he touted the benefits of the Snow Leopard version while taking a few digs at the then upcoming Windows 7, calling it just another version of Windows Vista.

Currently in preview mode, Lion, the next version of Mac OS X, is due to be released this summer.

After joining Apple in 1997, Serlet was promoted to senior vice president of software engineering in 2003, giving him responsibility for the largest part of the Mac OS software engineering group. Before launching his career with Apple, Serlet spent four years at Xerox PARC and also worked at Steve Jobs' NeXT endeavor starting in 1989. Serlet holds a doctorate in computer science from the University of Orsay in France.

Like Serlet, Federighi also worked at NeXT before joining Apple. He left Apple to work at Ariba for 10 years where he held several titles, including chief technology officer and vice president of Internet services. He then returned to Apple in 2009 to head the Mac OS X engineering team. He holds an MS in computer science and a BS in electrical engineering and computer science from the University of California at Berkeley.