Armstrong studied architecture at the Architectural Association School of Architecture and has had a career working on projects in London, Tokyo, Hong Kong, Buenos Aires and the USA. He plays a unique role that combines his responsibilities as a permanent member of the Design Board - which allows him to have an overview of every project, harnessing the collective experience of the architects and Specialist Teams within the practice with close involvements in selected projects. His portfolio includes CityCenterDC in Washington, 50 United Nations Plaza in New York, Oceanwide Center in San Francisco, The Murray Hotel in Hong Kong and One Beverly Hills in Los Angeles. Armstrong has a keen interest in residential building trends, the ecology of the built environment and urban design across the world.