Erstwhile Susan was based on Helen R. Martin's novel Barnabetta, which previously had served as the basis for a play by Marian De Forest. Constance Binney plays the daughter of a strict Pennsylvania Dutch household. She is rescued from this atmosphere by her stepmother, who provides the girl with enough money to attend school out of state and start a new life. The film has been noted as a sociological curiosity, painting a bleak picture of Pennsylvania Dutch paternalism and offering a rare nice stepmother. Most of the villainy is in the capable hands of Anders Randolph, who during his long screen career menaced everyone from Douglas Fairbanks to Garbo to Laurel & Hardy.
by Hal Erickson synopsis