Mike Miller was born in 1937 and first became involved in activism as a student at the University of California, Berkeley, where he majored in political science and sociology and acted as a founding member of the leftist student government faction SLATE.

After 1962, Miller worked full-time for the Student Nonviolent Coordinating Committee, registering voters in Mississippi, among other accomplishments. In 1966, he accepted a job working for Saul Alinsky at the Industrial Areas Foundation, and in 1972 he returned to the Bay Area to begin the neighborhood organization and training work that has constituted the bulk of his career. With the Mission Coalition Organization (MCO), he worked to avert so-called urban renewal efforts, which in practice tended to break down neighborhoods that had historically been home to marginalized people. At the same time, the MCO participated in a Lyndon Johnson program called Model Cities, which was intended to fund and strengthen local, grassroots political power. As founder of the ORGANIZE! Training Center, Miller also began to train residents and union members in the organization techniques he had learned both from experience and from his work with Alinsky, going on to a sixty-year organizing career.