Robert Ellis studied at Northampton School of Art from 1944 to 1947. Between 1947 and 1949, he served with the 3 Group Bomber Command Photographic Unit of the Royal Air Force. He attended the Royal College of Art, London, from 1949 to 1952. In 1957, he travelled to Aotearoa to take up a position as senior lecturer at Elam School of Fine Arts, where he taught until 1994. In 1966, he married fellow artist Elizabeth Aroha Mountain (Ngāpuhi, Ngāti Porou). Ellis increasingly made use of motifs and concepts from te ao Māori and the wider Moana (Pacific) region, fusing these with elements of British modernism.