SAN FRANCISCO (AFP) - Apple on Thursday (Dec 17) made shifts to its executive team, naming its first chief operating officer since Tim Cook moved into the chief executive job some four years ago.

Jeff Williams became Apple's chief operating officer, formalizing a role some contend he was already handling at the California-based technology colossus.

Mr Williams joined the company in 1998 and "played a key role in Apple's entry into the mobile phone market with the launch of the iPhone," according to a release.

Since 2010, Mr Williams' duties have included overseeing Apple's supply chain along with service and support.

"Jeff is hands-down the best operations executive I've ever worked with," Mr Cook said.

Apple senior vice president of worldwide marketing Phil Schiller, a familiar face to any who have tuned into the company's product unveilings, will expand his role to include heading the online App Store, according to the company.

The head of Apple's chip business, Johny Srouji, was named senior vice president for hardware technologies.

"Johny's team delivers world-class silicon designs which enable new innovations in our products year after year," Mr Cook said.

Mr Cook also announced that Tor Myhren will join Apple early next year as vice president of marketing communications, reporting Cook.

"We are fortunate to have incredible depth and breadth of talent across Apple's executive team," Mr Cook said.

Mr Cook was chief operating officer at Apple from 2007 to 2011 and took over as CEO from co-founder Steve Jobs, who died that year.