Brother Outsider relies on archival film footage and interviews to offer an incisive portrait of political activist Bayard Rustin. Although his name lacks the familiarity of other major Civil Rights leaders, the film shows that he nonetheless played a central role in the movement's seminal events during the 1950s and '60s. He traveled to Montgomery in 1956 during the bus boycotts where he advised Martin Luther King on non-violence, and served as the central organizer for the March on Washington in 1963. Rustin's political liabilities, however, often kept him out of the spotlight. He was a conscientious objector during World War II and, for a short time, belonged to the Communist Party. More problematic, however, was Rustin's homosexuality. His political enemies used his sexual orientation to neutralize him, while his political allies often shunned him because of it. Rustin also advocated for nuclear non-proliferation, and traveled to the Algerian Sahara to protest the first French nuclear test in 1960. Brother Outsider includes ample footage of Rustin himself, adding an autobiographical aspect to this feisty portrait.