Cuming was born in London of English, Scottish and Irish ancestry. He received his art education at Sidcup School of Art (1945–9) and, after National Service, at the Royal College of Art. He was awarded the Abbey Minor Travelling Scholarship to visit Italy. In 1964, he was elected an Associate of the Royal Academy (ARA), and a Royal Academician (RA) in 1974. He is also a member of the New English Art Club. As well as continuing to paint Italian scenes, including Venice, he still devotes much time to the landscape of the Southern English coastline, including Hastings and Rye. His art has an impressionist quality which captures "the fleeting impressions of his surroundings." He first encountered such landscapes as a child evacuee during the Blitz. The powerful contrast to his home in London created an enduring love for it. He lives in Rye, near Ashford, Kent.