His father was head of the British Royal Wheat Commission, and Hughes spent his childhood moving from country to country as his father was transferred in government service; consequently, his early schooling was acquired in South America, Canada, Mozambique, East Africa and other places.

At the age of 18, he joined the Royal Navy as a signalman and at the end of the Second World War, he left the service as lieutenant commander.

Robin Hughes addressed in an episode of the 1950s' television programme One Step Beyond that he was supposed to be assigned to HMS Hood on the morning of 24 May 1941, when it sank under enemy attack by the German battleship Bismarck.

In 1958 he appeared as the amorous editor Brian O'Bannion in Auntie Mame opposite Rosalind Russell.

He is also known for playing the title role (Satan) in The Twilight Zone episode "The Howling Man".