After World War I, Stephenson remained in London and studied at the Architectural Association School (AA) under Percy Hayman Meldrum and joined the Royal Institute of British Architects (RIBA) in 1920.
[6] The early 20th century saw advancements in medical technology and treatments, which transformed hospitals into a symbol of modern and healthy society.
[7] Stephenson took full advantage of this and traveled to America in 1926–7 to research the most modern developments in hospital design and equipment.
It wasn't until after Stephenson's second research trip in 1932–33 to continental Europe that hospital design in Australia drastically changed.
[7] Their next project, the Mercy Hospital (1934-5), introduced a completely new aesthetic : a six-level reinforced-concrete building with stark white sweeping cantilevered balconies that allowed for sun control and outdoor space for patients.
Stephenson and Turner designed the Australian pavilions at three international exhibitions, which demonstrated both his commitment to Modernism and the firms status.
[11] The 1939 New York World's Fair work was an interior design only, as it was an attached wing of the British Pavilion (Stanley Hall & Easton and Robertson) and was noted for collaborations with artists and photographers to create a dynamic modern experience; the United States honoured Stephenson with citizenship for his work.
[citation needed] They applied the same rigorous approach to researching and engaging with state of the art technologies and methods of manufacturing.
Their design for the General Motors Holden Factory complex (1954–56) in Dandenong featured a curtain wall to the administration building.
[citation needed] As well as major buildings in every capital city in Australia, in New Zealand, and a hospital in Basra, Iraq, Stephenson and Turner grew to become the largest Australian architecture firm of its time, with 300–400 staff at its peak.
Stephenson & Turner operates out of five bases in New Zealand, specialising in social infrastructure buildings and carrying on its heritage in healthcare architecture.