In 1899 Frances Macdonald joined MacNair in Liverpool and the two married. The couple painted watercolours and designed interiors, exhibiting a Writing Room at the International Exhibition of Modern Art in Turin. They also exhibited in Liverpool, London, Vienna and Dresden in the early 1900s. Following closure of the School in 1905, and the loss of the MacNair family wealth through business failure, the couple returned to Glasgow in 1909. MacNair's career went into decline from this period, and no works of his are known beyond 1911.