Thorstein Veblen was influenced by him, having written a piece on Gustav von Schmoller's Economics.
William J. Ashley, gave his inaugural address to the University of Toronto with a dedication to Gustav Schmoller on page 2.
W.E.B. DuBois, like Emily Balch, studied under Schmoller.
Richard T. Ely, Florence Kelley, John Graham Brooks, and Henry Carter Adams were all students of Schmoller's in their travels to Germany. Florence Kelley would be involved in various publications, she translated one of Friedrich Engel's works into English, but probably most notably, one of Florence Kelley's protege's was Frances Perkins, an appointee of FDR to Labor Secretary. Henry Carter Adams was an advisor to Committee on Interstate Commerce.
As you can see, at several times the ideas that this guy planted in others would end up directly shaping American policy.