Reporting into James Purnell, director of strategy and digital, Shield will oversee comms strategy as well as leading the Public Affairs and Communications Group.
He joins from the DWP where he is currently director of comms, and takes up his new role in November.
His appointment follows the announced departure of former comms head Paul Mylrea, and a traumatic year for the BBC labelled an 'annus horribilis' by culture secretary Maria Miller.
This includes the current storm over executive pay-offs and the Jimmy Savile scandal, during which the comms team came under heavy scrutiny.
Shield previously worked at the BBC for two years from 2008 as head of comms for journalism, but left to join public transport company Go-Ahead in 2010.
He joined the DWP a year later, and since then has speaheaded campaigning around Iain Duncan Smith's major welfare reforms.
Julian Payne, who held the role on an interim basis, will move to lead the BBC's recently announced review of Trust and Executive working practices.
BBC director general Tony Hall said: "John is a first class director of comms with a wide range of experience across broadcasting, government, and the commercial sector. He joins the BBC at an incredibly important time for the corporation as we strive to re-establish trust with our audiences and move towards a new chapter in the BBC’s history.
"I’d also like to thank Julian Payne who has worked tirelessly both with myself and Tim Davie over the past months, and with whom I look forward to continuing to work on the review of Trust and Executive working practices."
Shield said: "The BBC is one of the most talked about, hotly debated and important of our institutions - touching the lives of millions of people here and around the world every day. For these reasons, it is a demanding but fascinating challenge - I look forward to leading an excellent communications team in taking it on."
A Whitehall veteran, Shield's career has also taken in stints at the Department of Communities and Local Government and Department for Education and Skills.