Mackintosh was part of the Arts and Crafts movement and occasionally accused of being a part of the decadent Arts Nouveau school, which was looked upon with distrust by England. He helped found the Glasgow School of Art, which is now the Mackintosh Building. He was celebrated in Vienna, but, as above, largely ignored in his homeland--especially because of his difficult-to-grasp concept of total design in architecture. He died in the south of France in 1928 of cancer, having given up architecture and turned to landscape painting in his last years.

He and his friend Herbert MacNair also worked with the artist sisters, Margaret and Frances Macdonald. Together they embraced the "crafts" portion of the movement by working on not just illustration but also furniture and metalwork. They were derisively called "the Spook School."

Among his most recognizable and still-reproduced motifs is an abstracted, squared-off rose. One of the most common Art Nouveau fonts is a copy of Mackintosh's lettering, with rounded corners, high crosspieces and extra elements such as dots and double lines.