Schrag received encouragement in his early decision on a career in art from is father, a prominent lawyer in his native Karlsruhe. The future artist moved with his family to Zurich in 1930 but went to Geneva, Switzerland, to begin his art studies at the Ecole des Beaux-Arts there. He then went to Paris where he matriculated at the Ecole Nationale Superierure des Beaux-Arts, the Academie Ranson, and the Academie de La Grande Chaumiere. One of his teachers was Roger BissiŠre.
Schrag moved to New York in 1938 and studied printmaking at the Art Students League. His first solo exhibition in this country was held in 1947 at the Kraushaar Gallery which continued to represent him for the rest of his life. He was best known for his landscapes, many of which took their inspiration from the area around Dear Isle, Maine, where Schrag spent many summers. His style has been compared to those of Van Gogh, Matisse, Kirchner, and Charles Burchfield.
Schrag was also a printmaker and, in the late 1940s, worked at Stanley William Hayeter's Atelier 17. He taught printmaking at Brooklyn College (1953-54) and Cooper Union (1954-68).
Among his honors were a Ford Foundation Retrospective Exhibiton; the drawing prize, Ball State University, Indiana; the Child Hassam Purchase Award, the American Academy and Institute of Arts and Letters; and the James R. Marsh Memorial Award, the Society of American Graphic Artists. Retrospective exhibitions of his work were held at the Brooklyn Museum in 1960 and at the Farnsworth Art Museum, Rockland, Maine, in 1992.
