De Coux developed an early interest in the carving and modeling of figures and groups in wood and wax. During her youth, her family moved to Pittsburgh, Pennsylvania, and there, from 1925 to 1927, she pursued formal art studies at the Carnegie Institute. She continued her training at the New York School of Industrial Art, the Rhode Island School of Design in Providence, and at the Art Institute of Chicago while working in the studios of several prominent sculptors including those of C. Paul Jennewein and James Earle Fraser.
She traveled in Europe in 1935, and the following year established a studio in Gibsonia, Pennsylvania. De Coux received a Guggenheim Fellowship in 1939. From 1942 to 1945 she was a resident instructor at Cranbrook Academy, Bloomfield Hills, Michigan. She has specialized in biblical subjects and architectural sculpture, and has shown models for several of these, among other works in Academy annual exhibitions since 1937.
