Hugo Barra, the executive charged with leading Xiaomi's international expansion after being poached from Google in 2013, will leave the Chinese high-tech group at a critical time in the company.
In a Facebook post on Monday, Barra, who was Xiaomi's vice-president of international, praised the "rockstar start-up" but said the role had impacted his health.
"What I've realized is that the last few years of living in such a singular environment have taken a huge toll on my life and started affecting my health," Barra wrote.
"My friends, what I consider to be my home, and my life are back in Silicon Valley, which is also much closer to my family. Seeing how much I've left behind these past few years, it is clear to me that the time has come to return."
Barra said he would transition out of his role in February after the Chinese New Year and take some "much-needed time off before embarking on a new adventure back in Silicon Valley". He has been with the firm for three-and-a-half years.
The executive's departure comes at a difficult time for Xiaomi as it faces questions over growth. In a letter to staff this month, Xiaomi chief executive Lei Jun admitted the company had grown "too fast".
Xiaomi was once the darling of the smartphone world, showing triple-digit growth and challenging the likes of Samsung and Apple. But it has been struggling in the past two years and has since looked to branch into new areas.
Barra's role was to expand Xiaomi into markets, which has so far seen mixed success. India is Xiaomi's biggest market outside of China and last year generated $1 billion in annual revenue. Barra said the company has expanded into Indonesia, Singapore, Malaysia, and more recently 20 other markets including Russia, Mexico, and Poland.
Xiaomi has also been expanding into new product categories as the smartphone market matures.
The head of international for Xiaomi was hired from Google in 2013 where he was a vice president working on the Android mobile operating system. Xiang Wang, a Xiaomi senior vice president, will now head up international efforts, according to the company's President Bin Lin.