Among his sitters for portraits were Martin A. Ryerson, J. Ogden Armour, N. W. Harris, Harry P. Judson, and Peter S. Grosscup. He received the silver medal at the Saint Louis Exposition in 1904; gold medals at the International Exposition, Munich, in 1905, and at the Paris Salon in 1913 (the first American so honored); and was awarded the medal of honor at the Panama–Pacific International Exposition in 1915. Parker was also the president of the Rodin Studios corporation, which developed an artists' cooperative housing of the same name in New York City.