Southern was educated at
St Dunstan's College, London, then at Goldsmiths Art School and the
Royal Academy of Art, where he trained as a designer. Starting out in acting and stage managing, he designed sets for some fifty productions, staged at the
Everyman Theatre, the
Cambridge Festival Theatre, and London venues. In 1947, Southern was appointed theatre planning adviser to the
Arts Council. His investigation and reconstruction of period theatres and stages included work on Georgian theatres in
Richmond, Yorkshire, and
King's Lynn, Norfolk. He also took a leading role in the restoration of the first American theatre in
Colonial Williamsburg,
Virginia. Together with
George Speaight and
Sybil Rosenfeld, Southern was a founder of the Society for Theatre Research which was supported by a journal,
Theatre Notebook, which he co-edited for nine years. In 1951, Southern designed the Studio Theatre for the newly formed Drama Department of the
University of Bristol, where he lectured over the following two decades. In 1964, Southern was appointed a director of the
Nuffield Theatre, University of Southampton, on whose design he had worked in collaboration with architect Sir
Basil Spence. In the course of his career, Southern planned several modern theatres and stages including the
Royal College of Art (1952),
Reading University (1957),
Nottingham (1961) and
University College London (1967). After his retirement in 1969, he participated in the construction of the
Globe Theatre in London, partly based on his earlier models of the
Swan Theatre. ==Teaching activity==