After taking a correspondence course in drawing from Percy Bradshaw's Press Art School in London, Pett began to contribute cartoons to Punch, Passing Show and other publications, including children's comics. He also taught art at Moseley Road Junior Art School in Birmingham. Pett is the creator of the famous Second World War comic heroine, Jane. Jane was "born" in 1932, when 'Jane's Journal, the Diary of a Bright Young Thing' was launched in the Daily Mirror. As war broke out, Jane (who was modeled after Pett's wife), shed more and more clothes, thus keeping up the morale of servicemen both at home and abroad.