Mavis Belisle began social activism as a high school student with integration efforts in Oak Cliff. She became an anti-nuclear weapons activist as a Peace Corps volunteer in Micronesia.
She was a board member of the Dallas Peace Center, director of the Peace Farm outside the Pantex nuclear weapons plant near Amarillo for more than 16 years, and has led civil disobedience activities in several places in Texas, including opposition to the Comanche Peak nuclear power plant.
She is a board member of the Alliance for Nuclear Accountability, and a member of the National Committee of War Resisters League, with which she has worked since the 1970s.
She is currently co-chair with Lon Burnam of the Nuclear Free World Committee