Barley reports to UK managing director Neil Holloway and replaces Oliver Roll, who has been promoted to managing director of marketing for Asia Pacific. He will head a 90-strong marketing team and manage its £13m UK adspend.
The company has also hired former Cisco marketing chief Manda Rigby, who reports to Barley, to lead its assault on the big business sector as head of enterprise marketing. She left Cisco earlier this year.
Barley spent seven years at Oracle UK, most recently as vice-president and director of marketing.
Microsoft is understood to have received 250 applications for the position.
Barley was selected from a final shortlist of three.
He said: "IT industry marketers have focused too much on promoting the bells and whistles of technology rather than its relevance to the consumer. Microsoft is one of the few lifestyle brands in IT and is well placed to achieve this."