Born in Norfolk, Virginia, Couper studied in Munich and Florence, and remained in the latter city for 22 years before returning to the United States and establishing himself in New York in 1897 as a portraitist and sculptor of busts in the modern Italian manner.
He and Ball purchased a three-story brick building on 17th Street in Manhattan to serve as shared studio space. He sculpted the figure of the Roman goddess Flora for the exhibit of the Apollinaris Company at the Chicago World"s Fair in 1893. Couper retired from sculpting in 1913.
Couper is well known for his winged figures, such as the Recording Angel at the Couper family plot in Elmwood Cemetery in Norfolk and allegorical figures, such as Psyche and A Crown for the Victor, in the collection of the Montclair Art Museum.
Couper lived much of his life in Montclair, New Jersey, where he built a large neoclassical villa he named Poggioridente or "laughing knoll". He had a home in Cortland, New York, as well.
They had several sons, one of whom, Thomas Ball Couper, lived in Montclair.
Member jury for acceptance of works of art sent from Italy to Chicago Exposition, 1893, and other expns. in this country.
Married Eliza Chickering Ball, May 9, 1878.