Her role will be to provide strong and visible leadership for the Thames Gateway, in particular central and regional government and agency engagement, and support for local delivery vehicles and private sector investors.
Ruth Kelly said: 'I am delighted to announce this appointment. Judith has a proven track record of leadership and delivering high profile projects at Medway and will bring valuable skills and experience to this new role.
'The Thames Gateway gives us a unique opportunity to create the sort of communities in which we all want to live. We are moving into an exciting phase of that programme and I am confident Judith will lead its success.'
Judith Armitt was previously director of finance and support services at the London borough of Lewisham, and before that worked for the Greater London Council.
The Thames Gateway stretches for 40 miles along the Thames Estuary from the London Docklands to Southend in Essex and Sheerness in Kent.
By 2016, the government's targets for the Gateway include:
* 120,000 new homes including affordable units for rent or purchase by first time buyers including key workers, supported by high quality transport infrastructure
* Aiming for 180,000 new jobs through encouraging business and economic investment offering local residents a wider range of career options
* Improve education facilities to enhance the local skills base, helping residents to obtain jobs and better prospects
* All residents will have access to high quality healthcare, reducing the existing inequalities across the area
* Major improvement to the image and environment of the Gateway, including higher quality design and attractive open spaces, with improved green spaces and access to the river. To date, 82% of approved developments have been on brownfield sites