His original aim was to be an actor, and he did secure very minor parts in a number of films, e.g. To the Public Danger (1948), Double Confession (1950), but he soon drifted into broadcasting, coming to public notice as an announcer, and later producer, for the International Broadcasting Company (IBC), starting on Radio Normandy in April 1936 and moving on at the end of that year to the IBC's Paris-based station, Poste Parisien.

Between mid-1937 and late 1939, he was involved in writing and production, travelling back and forth between these two IBC stations in France and the company's offices and studios in London, while also presenting the variety programme Radio Normandy Calling, recorded on location in theatres at UK seaside resorts and regularly beating the BBC in audience ratings.

[2] This part of his career came to an abrupt end when commercial broadcasting from the continent was brought to a halt by World War II.

Plomley and his new wife, Diana Wong, whom he married earlier that year, stayed on in Paris, only narrowly escaping back to the UK via a circuitous route through the chaos and panic of the Fall of France, losing all their possessions in the process, as German occupying forces approached the French capital in June 1940.

[1] Plomley was succeeded as presenter by Michael Parkinson (1986–1988), then by Sue Lawley (1988–2006), Kirsty Young (2006–2018) and most recently by Lauren Laverne.

At his death, those 'rights' passed to his widow, and the BBC were subsequently unable to negotiate the right to include Desert Island Discs in their Listen Again offering.