McBrien is the new head of customer relationship management for Europe, the Middle East and Africa. He reports to marketing director Neil Thompson.
He was previously head of direct marketing at the video-on-demand company HomeChoice and a subscriptions marketer at BSkyB.
McBrien will identify Xbox owners most likely to adopt Live and establish an ongoing dialogue with them to buy more online games. He will also oversee relationship marketing initiatives for the Xbox.
Xbox Live launches across Europe on March 14, exactly a year after the console's launch. Microsoft's plans for Xbox Live are believed to be the most advanced in the online arena of any of the consoles. It will allow gamers to play and hear each other over a broadband internet connection.
Users will need to buy a starter pack and take out a monthly subscription to the service, which began operating trials in November.
Xbox and Nintendo's GameCube, both launched last year, have yet to make a real impact on Sony PlayStation's market lead. Online gaming is Microsoft's main strategy against PlayStation 2.
Agency Republic and AKQA will market Live to existing Xbox customers while Bartle Bogle Hegarty is creating advertising to promote its launch.
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