[1][3][4] Coolidge studied painting with Hamilton Easter Field and Robert Henri, and he also had associations with Marsden Hartley and Bernard Karfiol, among others.
[1][4][5] He was a member of the Société Nationale des Beaux-Arts[6] and exhibited at distinguished galleries across the United States and Europe,[1][4][7] particularly in New York City, where some of his work was shown at the MacDowell Club alongside paintings by Edward Hopper.
[3][10] In a review of the show, an article in American Art News wrote that Coolidge "inclines to the formula of Post-Impressionism" and that he "seeks beauty in form rather than in atmosphere; his landscapes are undulating and solid, even the rocks having curling contours, and his colors are dull and deep.
[4][11] One such article, in a 1913 issue of the Spokesman-Review, juxtaposes a caricature of Coolidge's painting with Futurist works by Carlo Carrà and Umberto Boccioni.
[13][14] Coolidge had an intimate lifelong relationship with the painter Channing Hare, with whom he also ran a small antique shop in Ogunquit.