Paul Cornoyer was born in St. Louis, Missouri, in 1864, and studied at the School of Fine Arts in 1881. Rustic scenes typified his early work, before he traveled to Paris in 1889 to study with French artists Jules-Joseph Lefebvre, Benjamin Constant and Louis Blanc. By the early 1890s, Cornoyer's work had acquired a more lyrical, tonal approach which he employed in his expression of both landscapes and city scenes. His mature style is not unlike that of another important American painter, Childe Hassam.
Returning to St. Louis by 1894, Cornoyer painted a mural depicting the birth of St. Louis for the Planter's Hotel. Another memorable work from this time was his triptych, A View of St. Louis, which featured St. Louis' Eads Bridge, the bridge being a seminal monument of urban modernity comparable to New York's Brooklyn Bridge. In 1895, Cornoyer became a founding member - along with fellow artists Edmund H. Wuerpel, Martha Hoke, Holmes Smith, and Edward Campbell - of the Saint Louis Association of Painters and Sculptors, an organization formed to exhibit their work, which they did in the galleries of the old Saint Louis Museum.
William Merritt Chase had become a patron of Cornoyer's, and it was at Chase's urging that the artist moved to New York City in 1899. In New York, Cornoyer concentrated on urban scenes, favoring views of parks such as is seen in his painting Union Square Park. It was in New York that he painted one of his best-known paintings, The Plaza After Rain, which was acquired in 1910 by the new art museum in St. Louis. In line with his tendency to document significant features of urban development, Cornoyer's also painted views of Dewey’s Arch and the Third Avenue elevated.
The National Academy of Design records show, that from 1903-1923, Cornoyer exhibited many New York-subject paintings with titles such as Madison Square, New York Central Excavation, Columbus Circle, and Bryant Park. During the summers Cornoyer lived in Gloucester, Massachusetts. Cornoyer exhibited widely, and was a member of the National Academy of Design, Salmagundi Club, Allied American Artists, and the National Arts Club. His paintings are found in the collections of the Brooklyn Institute, Dallas Art Association, and the Newark Art Association, to name but a few.