Mr Ennis, who is currently executive director of corporate resources, will be responsible for all operational issues at the housing and regeneration quango.
He is due to take up his new position, based in the agency’s Victoria office, on 20 April 2009.
His responsibilities cover finance, human resources, IT, legal services, corporate assurance, facilities management, health and safety, and procurement.
HCA chief executive Sir Bob Kerslake said: “Richard has extensive experience in senior finance roles and I am very pleased that the HCA has recruited yet another high calibre senior manager.
"Ealing’s loss is most definitely the HCA’s gain in this instance, although I genuinely believe that the benefits of a strong senior management team here will be felt by our key local authority partners everywhere.