He was a close friend of Walter de la Mare, whom he first met in 1913, and about whose fiction he published a perceptive book in 1929. Reid was also an influence on novelist Stephen Gilbert, and had good connections to the Bloomsbury Group of writers. Reid was a founding member of the Imperial Art League (later the Artists League of Great Britain). Reid was also a close friend of Arthur Greeves, the artist known to be C. S. Lewis's best friend. Greeves painted several portraits of Reid, now all in the possession of the Royal Belfast Academical Institution.