Falmouth-born Cox never attended art school and trained as engineer.  Unfit for active service during WWII due to a perforated ulcer, he started painting seriously c1942 whilst at Taunton. (Buckman, however, says that he studied art in London, France and Italy.)

He moved to Cubert near Newquay in 1944 and exhibited in St Ives in 1946 at Show Day in Borlase SMART's studio (an admirer of his work).  The Times (March 1946) noted that his landscapes were characterized by "a certain grey misty effect that never obscures his object but gives [them] an atmosphere all his own" 

Cox moved to St Ives in 1947, and took over Smart's Porthmeor studio after Smart's death, sharing it with Leonard RICHMOND; Bernard Fleetwood WALKER also used the studio occasionally.

Cox developed a more Impressionistic style focused on young semi-nude girls and portraits.  As Secretary of STISA he organized the Touring Exhibition (which attracted 1,900 visitors) and the Full Touring Show in 1947, which  took in Newquay, Fowey, Falmouth and Truro. He left St Ives in 1950 to move to Essex where he ran his own art school for several decades.