 In each of the three states, he also served as president of the state's teachers' association and on the state board of education.He was a devotee of the progressive principles of education reformer John Dewey.He served as the president of the National Education Association's Department of Superintendence in 1908, having previously been the department's secretary in 1901 and its vice-president in 1898.

Cooper served as the superintendent of public schools in Le Mars, Iowa, from 1883 to 1890.