Architect and designer. Born in Glasgow and educated in Greenock, MacNair became an apprentice in a Glasgow architectural practice. He took evening classes at Glasgow School of Art with designer Charles Rennie Mackintosh (1868 - 1928). He started a design business, specialising in furniture, posters and book illustration. He took a post in the University of Liverpool in 1897 and went on to design a Writing Room for the Scottish Pavilion at the International Exhibition in Turin (1902), in which Mackintosh also took a prominent role.
In 1899, MacNair married artist Frances MacDonald (1834 - 1921), whose sister, Margaret (1865 - 1933), married his friend Mackintosh.
He returned to Glasgow in 1909, but the couple suffered severe financial difficulties and were disowned by MacDonald's family. After the early death of his wife in 1921, MacNair vowed never to paint again and destroyed a significant number of paintings by Frances and himself. His paintings, which often show a mystical quality, can be seen in the Kelvingrove Art Gallery, Hunterian Gallery (both in Glasgow) and the Walker Art Gallery (Liverpool).
