Lord Warner, who resigned from the government two months ago, will front London's Provider Development Agency from next month.
The agency will manage and develop the performance of London's provider organisations. A spokesman for NHS London said one of its challenges would be to see that all NHS-owned provision was delivered by foundation trusts.
NHS London chief executive Ruth Carnall previously told HSJ that the agency's independence from the strategic health authority would enable it to push the provider reform agenda more effectively.
Lord Warner, who as health minister championed foundation trusts during the controversial passage of the bill to create them, said: 'The agency is the first of its kind in England, driving forward continuing improvements to deliver foundation status for acute trusts in London. Our priorities will be to ensure services are properly planned and managed to deliver reform and excellent healthcare in the capital.'
NHS London has made two other high-profile appointments this week: Antony Sumara has been appointed turnaround director and Paul Baumann is the new director of finance and performance.
Mr Sumara took up his post on Monday but will continue in his current role as interim chief executive at Hillingdon primary care trust.
During his tenure at Hillingdon Mr Sumara has reduced the forecast deficit of the PCT from£22.5m to£11m.
Mr Baumann worked at household goods multinational Unilever for the last 20 years, and Unison said it had concerns about his appointment.
Unison head of health Karen Jennings said: 'He does not have any record in the public sector which we would be concerned about in terms of bringing in more competition rather than a co-operative approach.'