Apple named Jeff Williams as its new chief operating officer, a job that hasn't been filled since Tim Cook left the position more than four years ago to become CEO.

Williams has worked at Apple for about 17 years and supervised the launch of the Apple Watch, which went on sale earlier this year.

The company said Thursday he also played a key role in the launch of the iPhone.

Apple Inc., based in Cupertino, California, also named Johny Srouji as senior vice president.