Milton is the founder and director of the Intercultural Development Research Institute co-located in Oregon, USA and Milan, Italy and was a founding director of the Intercultural Communication Institute in Portland, Oregon. He was a tenured faculty member in the Department of Communication Studies at Portland State University, where he created their graduate program in intercultural communication, and he is now an adjunct faculty member in the Department of Sociology at the University of Milano-Bicocca in Italy, where he teaches in the graduate program of Social Service Management and Political Policy.

He is on the faculty of several executive leadership programs and is a core faculty member in the IDRAcademy curriculum of constructivist intercultural communication. He is known for originating the Developmental Model of Intercultural Sensitivity and he is the co-author of American Cultural Pattern: A Cross-Cultural Approach, author and editor of Basic Concepts of Intercultural Communication: Paradigms, Principles, & Practices (published in English, Italian, and Chinese), and a contributing co-editor of the Handbook of Intercultural Training, 3rd Edition (also translated into Chinese). He consults with corporate and academic organizations in Europe, Asia, and the US on topics of multicultural diversity, intercultural competence, and global leadership.