Pitchforth began the Second World War painting scenes of bomb damage around London, first on short-term contracts, and, from 1940, as a salaried artist for the Wart Artists' Advisory Committee, before moving on to factory subjects or WAAFs themes. In the spring of 1943, he was assigned to the Admiralty, when his focus shifted to maritime warfare, recording a variey of vessels and subjects in London, Birmingham, Bristol, Manchester, the south coast of England, Scotland, Northern Ireland as well as sailing on convoys to Gibraltar and the Azores. He painted on board ships in the Western Approaches from Spring 1944, and in 1945 he was dispatched to the Far East to record the Allied campaigns in Burma and Ceylon.
Before and after the war, Pitchforth taught art, notably at St Martins School of Art, the Royal College of Art and Camberwell.