Howard Watson has been named CEO of BT Technology, Service and Operations (BT TSO) and Group Chief Information Officer following Clive Selley's appointment as Openreach CEO.
Watson is currently BT Chief Architect and Managing Director for Global IT Platforms.
He joined BT in 2011 from Cartesian, a telecoms software and consultancy company where he was Managing Director. Prior to that, he was Chief Technology and Information Officer at Telewest and Chief of Transformation and Technology at Virgin Media.
In his new role Watson will be in charge of the company's 'engine room', responsible for its core networks and IT systems across the globe.
BT TSO manage the company's internal and external platforms - including TV, Mobile and Conferencing - as well as BT's research and development arm at Adastral Park, Suffolk.
BT TSO employs 12,000 staff and 8,000 contractors across the world.
Watson also led the technical teams behind the launch of BT Sport in August 2013.
He said: "The next few years promise to be transformational in terms of how people communicate and I look forward to making my contribution."
Gavin Patterson, BT Group Chief Executive, said: "Howard has done a great job since joining BT in 2011 and is absolutely the right man to oversee the integration of our network with EE's. Fixed mobile convergence is an important trend and Howard will help consumers and businesses take advantage of it."