Michelle Mitchell will become senior charity director on 1 March, responsible for policy and influence.
She will be in charge of communicating the new charity's vision and policy perspectives, and positioning the charity as a global leader on age and ageing. She will also oversee all lobbying efforts.
The new charity will be launched in April.
Mitchell currently oversees a department of 74 and manages policy, public affairs, information, brand and events for Age Concern.
'I am absolutely determined to make sure that age and ageing issues are placed right at the centre of public policy debate, where it belongs. An ageing society deserves and demands high quality services, products and campaigns to help drive real positive change for older people', said Mitchell.
'The team I will be leading will work alongside policy-makers, key stakeholders, the media and others to drive that ambitious and challenging strategy forward and ensure that the new charity thrives and gets it message across in a clear, consistent and considered way.'