Apple Inc. has its new Tim Cook. On Thursday, Apple promoted Jeff Williams to the position of chief operating officer, filling a spot left vacant since Tim Cook was promoted from that position to CEO in 2011. It also named named Johny Srouji to its executive team as senior vice president for hardware technologies.

Prior to the promotion, Williams held the title of vice president of operations, overseeing the iPhone maker’s supply chain as well as the development of the Apple Watch.

Srouji previously held the title of vice president of hardware technologies, overseeing Apple’s custom chip and hardware development. He joined Apple in 2008 and was responsible for developing the first Apple-designed system-on-a-chip: the A4. In addition to these promotions, Senior Vice President of Marketing Phil Schiller has been tasked with the responsibility of developing strategies to expand the App Store for all its products, including the iPhone, iPad, iPod Touch, Mac and Apple TV. Apple Senior Vice President of Internet Software and Services Eddy Cue had previously been the sole person responsible for overseeing the App Store.

“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,” Cook said in a press statement. “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.”

Starting in 2016, Tor Myhren, chief creative officer of advertising firm Grey Group, will also join Apple as vice president of marketing communications. In his new role, Myhren will spearhead the company’s advertising efforts as well as lead its creative teams to develop video, motion graphics, web design, packaging and retail store displays. Myhren replaces Hiroki Asai, who served for 18 years in various graphic design and marketing communication roles at Apple.