Born in Hampshire, Benjamin studied engineering for four years at the Regent Street Polytechnic before becoming an artist. After some months studying drawing at Leger's studio in Paris, he arrived in St Ives in 1955. Buckman reports that here he split his time between flower-growing and abstract landscape painting, and leading an artistic life somewhat apart from the general circle of working artists. Benjamin took over the cottage and land formerly inhabited by the controversial and colourful Sven BERLIN.  He was away for one year (1958-59) on a French Government fellowship allowing him to study with S W Hayter at Studio 17 in printmaking.

That same year he was part of a mixed show, entitled Twenty Cornish Artists sponsored by the Falmouth Art Group at their Polytechnic Gallery, a show that was shared with Newlyn Art Gallery and the Penwith Gallery in St Ives. This was to be seen as establishing his credentials in the Cornish art world and became a springboard to wider exhibiting. In 1960 Benjamin was selected by Michael CANNEY, curator of NAG, to exhibit in the Painters in Cornwall 1960 Exhibition in the City Art Gallery, Plymouth. (See Hardie 100 Years, p 122). In 1962 Canney, with the architect and painter John MILLER, redesigned the Fore Street Gallery in St Ives and the Lower Gallery at Newlyn, and Benjamin was offered one of the first one-man shows that followed.

Financial pressures, and the need to earn a living, meant that he had to leave Cornwall. By this time he was working also from London, and accepted teaching/lecturing posts in Canada and the USA. An impressive range of group and solo shows followed, and Benjamin's work became widely recognised and respected.

He returned to London in 1973, settling with his Canadian partner and sons at Kelling Village Holt, Norfolk where he continued to work up until his death in 2002.