Born in Vienna where she studied piano privately with Richard Robert and Karl Weigl whom she married. Then Vally Weigl studied music at the University of Vienna.
After the Anschluss she left for the USA (1938), where she taught at different colleges (from 1942). Weigl studied at the Teachers College of Columbia University (1951-1953), and became Music therapist at the at the Roosevelt Cerebral Palsy School in Roosevelt N.Y. (1955-1976). She was also music therapist at the Jewish Home for the Aged in New York (1966), and different other institutions. Vally Weigl also composed music; her best known works are: Hymn for 5 part choir a capella (1944); New England Suite for clarinet, violin and piano (1955).