Cooper exhibited at the Royal Academy Summer Exhibition on at least 22 occasions, between 1911 and 1972. Some versions record or suggest 40 occasions. His first accepted painting, executed while still a student, was The Pardon, an oil painting (1911). Cooper's 1921 submission to the RA was London From an Airship, "a notable feature" of the exhibition. In 1925, he exhibited Le Rêve, "an extremely thin nude figure ... shows considerable technical accomplishment". In 1930 Cooper contributed a portrait of the actress Miss Norah Baring in dramatic pose. In 1933, he exhibited two oil paintings: Miss Jessica Tandy as Manuela in "Children in Uniform", which "won immediate success", and A Dorset Beach. The Tandy portrait was reproduced in various newspapers, and Cooper was photographed at his easel, in his studio with Tandy. In 1937, Cooper's contribution was a portrait, Marquess of Carisbrooke, "a resplendent figure in robes". In 1944 he exhibited his "massive" Derby Day, and his Dressing Table, "a lovely and attractive portrait". Cooper's 1950 contribution was The Dancer, a head-and-shoulders profile portrait in oils of the sitter in a balletic pose but wearing a jumper. In 1972 he contributed his last two paintings to the exhibition: the oil painting Dorset Beach again, and a watercolour The Life Class. In April 1934 at the Royal Academy Summer Exhibition Cooper exhibited his Derby Day Seventy-Seven Years After Frith painting, which was a tribute to the earlier work, William Powell Frith's Derby Day. In Cooper's painting, two bookies' stands are given the names of two of his artist friends, Philip Connard and Adrian Scott Stokes: a "leg pull" which amused other artists. Cooper said, "Both are friends of mine, and I thought it would be rather a lark to put their names on the canvas. Now the other members of the club are having a great time at their expense". His portrait of Winston Churchill, later named Profile for Victory, was hung in the Royal Academy Summer Exhibition of 1943; the Tatler said that it was the "first profile portrait to be exhibited of the Prime Minister". Other exhibition venues Cooper exhibited at the Royal College of Art, and he "received an hon. mention at the Paris Salon 1924". In 1934 he exhibited a painting of three nudes to a show at Leger's Galleries called The Nude in Contemporary British Art. At the United Artists' exhibition at the Royal Academy galleries