(Yicai Global) Nov. 14 -- Harry Shum, the highest-ranking Chinese executive at Microsoft, has handed in his notice after a 23-year stint at the software giant and may be headed back to his homeland.

"Leaving Microsoft is the toughest decision of my life," tech news outlet ZDNet cited the 53-year-old as saying in a recent circular to employees of the Washington-based firm. "Microsoft has been very successful, but at this stage of my life, it is time to open a new chapter. It's time to explore new challenges beyond Microsoft and beyond business; to think about what I can do more for the industry and the next generation of computing science," he added.

He will officially resign from his post on Feb. 1, with Chief Technology Officer Kevin Scott taking over his position in the interim, according to the report.

Shum's latest roles at the company have been global executive vice president and executive vice president of artificial intelligence and research. He joined Microsoft in 1996 and some of his biggest achievements include co-founding Microsoft Research Asia in 1998 and leading development of search engine Bing and AI assistant Cortana.

A source familiar with the matter told Yicai Global that Shum is likely to head back to China to further his career, following in the footsteps of Microsoft's previous top-level Chinese executive.

Executive Vice President Lu Qi ended his eight-year stint at Microsoft in 2016 before joining Chinese rival Baidu the following year. Lu now leads China exploration for American startup incubator Y Combinator.

Editor: James Boynton