This article addresses the sociological approach and political engagements of the early twentieth century sociologist, Herbert Adolphus Miller (1875–1951). He is now largely forgotten, but he had deep connections within the Chicago milieu of pragmatist sociology and social reform activities through both the Settlement movement and the Survey movement. In 1914 he wrote a volume in the Cleveland Survey on Immigrant children in the school system and in 1918 was appointed to head the division on Immigrant Contributions in the Carnegie Corporation’s project on ‘Methods of Americanization’, in which Robert E. Park was head of the division on Immigrant Press and Theater (Park in The Immigrant Press, 1922). If Miller’s name is recognized at all it is as author with Park of Old World Traits Transplanted (1921), a work subsequently attributed to W. I. Thomas. We examine the nature of Miller’s research on immigrant populations from subject nationalities in Europe, undertaken in Cleveland and as part of the Carnegie project. He left the latter project mid-way through to become part of a small group that drafted the Czechoslovakian Declaration of Independence in November 1918. We show how Miller developed a distinctive approach to ‘Americanization’ through his idea of ‘proportional patriotism’ that challenged the dominant discourse of assimilation that became entrenched in the years after the end of the first world war and which was largely accepted by Park and by Thomas. He was dismissed in 1932 from Ohio State University because of his views on race mixing and his criticisms of the British and Japanese empires.