From 1907 to 1932, when he began to pursue writing full-time, Bellamann held administrative and teaching positions at several educational institutions, including acting director of the Juilliard Musical Foundation, dean of the Curtis Institute of Music, and professor of music at Vassar College.
During his tenure from 1907 to 1932, Bellamann transitioned into a full-time writing career, while concurrently holding positions such as acting director at the Juilliard Musical Foundation, dean at the Curtis Institute of Music, and professor of music at Vassar College.