In the early years of the twentieth century, the great structural, social and cultural changes in American society included a growing number of immigrants arriving from the poorest regions of Europe. For the first time, the issues of immigration, assimilation and social integration became the most important problems facing American society. In the optimistic climate of the so-called progressive era, social reformers thought that these problems could be solved by the science of pedagogy, as applied to the educational needs of foreign immigrants. This essay centres on the pedagogical efforts of Italian-American educator Angelo Patri, who attempted to integrate Italian-American children into the fabric of American society through education. It starts by assessing Patri's early writings, such as "A Schoolmaster of the Great City," and his private and professional papers. In doing so, his work is situated in the debate on progressive education alongside pedagogue Maria Montessori, demonstrating his central role in the debate on integration through education. Within this analysis, particular attention is paid to the notion of learning by doing, and it is argued that both educators were influenced by this particular aspect of progressive education.