Born in Hawick, McNairn was encouraged by his father, an amateur painter, to enroll at Edinburgh College of Art. He began in 1927, a time of extreme creativity following the end of the First World War. On graduation McNairn travelled to Paris where he attended the Académie Scandinave, drawn by the presence of the fauve artist, Othon Friesz. In 1933 he saw the surrealist exhibition in the city, which had a striking effect on him; he has stated the disturbing effect that Dalí and Miró had on him especially. This influence is identifiable in much of McNairn’s work through an unsettling emptiness and a slightly unnatural perspective. Following war service, McNairn returned to Scotland and became an art teacher.