Having worked at Apple for nearly three decades, Williams has played a significant role in introducing the iPod and iPhone programs, leading the development of the Apple Watch, and overseeing the design team,

Mr. Williams was long considered a leading candidate to replace Tim Cook as the company’s next chief executive.

In a major leadership shakeup at Apple Inc., longtime Chief Operating Officer Jeff Williams is set to retire, marking the exit of one of the company’s most influential figures. Apple confirmed on Tuesday that Williams will step down as COO this month and