Williams previously oversaw Apple's supply chain, the same job that current CEO Tim Cook used to do under Steve Jobs.
Apple mentions in its press release that Williams oversaw the development of the Apple Watch, the company's first wearable computing device that it launched earlier this year.
Williams was previously COO in everything but title. He worked as senior vice president, operations. Cook previously worked as COO before he took over as CEO in 2011.
The Wall Street Journal spoke to an anonymous senior executive at Apple who said that Williams' promotion isn't a sign that he's in line to be the next CEO. Instead, they said it formalises the role that Williams has been carrying out for years.
That's not the only change that Apple announced today. It also put veteran exec Phil Schiller in charge of the App Store.
The press release also says that Apple had promoted Johny Srouji to the position of senior vice president for hardware technologies, and advertising exec Tor Myhren will join the company as vice president of marketing communications early in 2016.
Here's the full press release from Apple:
Apple Names Jeff Williams Chief Operating Officer
Johny Srouji Named to Executive Team; Phil Schiller Adds Ecosystem Responsibilities
Tor Myhren Joins Apple
CUPERTINO, California - December 17, 2015 - Apple® today announced that Jeff Williams has been named chief operating officer and Johny Srouji is joining Apple's executive team as senior vice president for Hardware Technologies. Phil Schiller, senior vice president of Worldwide Marketing, will expand his role to include leadership of the revolutionary App Store® across all Apple platforms. Apple also announced that Tor Myhren will join Apple in the first calendar quarter of 2016 as vice president of Marketing Communications, reporting to CEO Tim Cook.
"We are fortunate to have incredible depth and breadth of talent across Apple's executive team. As we come to the end of the year, we're recognizing the contributions already being made by two key executives," said Tim Cook, Apple's CEO. "Jeff is hands-down the best operations executive I've ever worked with, and Johny's team delivers world-class silicon designs which enable new innovations in our products year after year."
Cook continued, "In addition, Phil is taking on new responsibilities for advancing our ecosystem, led by the App Store, which has grown from a single, groundbreaking iOS store into four powerful platforms and an increasingly important part of our business. And I'm incredibly happy to welcome Tor Myhren, who will bring his creative talents to our advertising and marcom functions."
Jeff joined Apple in 1998 as head of worldwide procurement and in 2004 he was named vice president of Operations. Since 2010 he has overseen Apple's entire supply chain, service and support, and the social responsibility initiatives which protect more than one million workers worldwide. Jeff played a key role in Apple's entry into the mobile phone market with the launch of iPhone®, and he continues to supervise development of Apple's first wearable product, Apple Watch®.
In nearly eight years at Apple as vice president of Hardware Technologies, Johny Srouji has built one of the world's strongest and most innovative teams of silicon and technology engineers, overseeing breakthrough custom silicon and hardware technologies including batteries, application processors, storage controllers, sensors silicon, display silicon and other chipsets across Apple's entire product line. Educated at Technion, Israel's Institute of Technology, Johny joined Apple in 2008 to lead development of the A4, the first Apple-designed system on a chip.
With added responsibility for the App Store, Phil Schiller will focus on strategies to extend the ecosystem Apple customers have come to love when using their iPhone, iPad®, Mac®, Apple Watch and Apple TV®. Phil now leads nearly all developer-related functions at Apple, in addition to his other marketing responsibilities including Worldwide Product Marketing, international marketing, education and business marketing. More than 11 million developers around the world create apps for Apple's four software platforms - iOS, OS X®, watchOS™ and tvOS™ - as well as compatible hardware and other accessories, and customers have downloaded more than 100 billion apps across those platforms.
Tor Myhren joins Apple from Grey Group, where he has served as chief creative officer and president of Grey New York. Under his leadership, Grey was named Adweek's Global Agency of the Year for both 2013 and 2015. As vice president of Marketing Communications at Apple, Tor will be responsible for Apple's advertising efforts and will lead an award-winning team that spans a broad range of creative disciplines from video, motion graphics and interactive web design to packaging and retail store displays.
Tor will succeed Hiroki Asai, who earlier announced plans to retire after 18 years in graphic design and marketing communications roles at Apple.
Apple revolutionized personal technology with the introduction of the Macintosh in 1984. Today, Apple leads the world in innovation with iPhone, iPad, Mac, Apple Watch and Apple TV. Apple's four software platforms - iOS, OS X, watchOS and tvOS - provide seamless experiences across all Apple devices and empower people with breakthrough services including the App Store, Apple Music, Apple Pay and iCloud. Apple's 100,000 employees are dedicated to making the best products on earth, and to leaving the world better than we found it.
This story is developing, refresh for updates.