His career of activism can be traced to his junior year at Bates, when he organized a sit-in at a local Maine restaurant that refused to serve people of color. It was his first foray into social activism, and he never looked back. Just a few years later, Stringfellow gained a reputation as a strident critic of the social, military and economic policies of the US and as a tireless advocate for racial and social justice. That justice, he declared, could be realized only if it were pursued according to a serious understanding of the Bible and the Christian faith. He was particularly active in the Civil Rights Movement and has spoken extensively about civil disobedience through nonviolence and integration, particularly in an interview with Robert Penn Warren for the book "Who Speaks for the Negro?".